It's a custom knockdown state. Here's what it looks like.

Spoiler, click to toggle visibilty

; Hit Fall

[Statedef 505]

type = A

movetype= H

physics = N

anim = 5030

facep2 = 1

[State 505, 1]

type = velset

trigger1 = time = 0

x = -3

y = -3

[State 505, 1]

type = veladd

trigger1 = time > 6

x = -0.2

y = 0.5

[State 505, Changestate]

type = changestate

triggerall = time > 1

trigger1 = pos Y >= 0

trigger1 = vel y > 0

value = 506

;--------------------------------------------------------------------------

; Hit Lie

[statedef 506]

type = U

movetype= H

physics = N

velset = -2,0

anim = 5100

facep2 = 1

[State 506, Changeanim]

type = changeanim

trigger1 = time = 55

value = 5110

[State 506, Posset]

type = posset

trigger1 = time = 0

y = 0

[State 506, Changestate]

type = selfstate

trigger1 = time >= 60

value = 5120

[State 506, Changestate]

type = selfstate

trigger1 = !alive

value = 5150

Just to be safe and make it easier on everyone, I'll also post the relevant codes for the assist itself.

Spoiler, click to toggle visibilty

; SOS Assists

[Statedef 2090]

type = A

physics = N

ctrl = 0

velset = 0,0

anim = 1

facep2 = 1

[State 2090, BindToRoot]

type = BindToRoot

trigger1 = 1

pos = 0,0

facing = 1

[State 2090, Assist Gauge]

type = explod

trigger1 = (NumExplod(11000) = 0)

anim = 11000

id = 11000

postype = left

pos = ifelse(TeamSide = 2,221,95),45

facing = ifelse(teamside = 1,1,1)

ontop = 1

sprpriority = 4

supermovetime = 99999

pausemovetime = 99999

removetime = -1

bindtime = -1

removeongethit = 0

ownpal = 1

ignorehitpause = 1

scale = 0.42,0.42

[State 2090, Yuki Call]

type = PlaySnd

triggerall = !numhelper(2100)

triggerall = root,movetype != H

triggerall = root,stateno != [120,155]

trigger1 = (root,power >= 500 && root,movetype = A) || root,ctrl

trigger1 = (root,command = "c") && !(root,command = "holdfwd" && root,command = "c") && !(root,command = "holdback" && root,command = "c") && !(root,command = "holddown" && root,command = "c") && !(root,command = "Burst")

value = 11,31

[State 2090, Yuki Meter]

type = explod

trigger1 = (NumExplod(11100) = 0)

anim = 11100

id = 11100

postype = left

pos = ifelse(TeamSide = 2,184,58),57

facing = ifelse(teamside = 1,1,1)

vfacing = -1

ontop = 0

sprpriority = 5

supermovetime = 99999

pausemovetime = 99999

removetime = -1

bindtime = -1

removeongethit = 0

ownpal = 1

ignorehitpause = 1

scale = 0.44,0.75

[State 3102, Yuki Meter Status]

type = ModifyExplod

triggerall = numhelper(2100)

trigger1 = root,fvar(7)

ID = 11100

scale = 0.00119+(root,fvar(7)/910),0.77

ignorehitpause = 1

[State 2090, Yuki]

type = Helper

triggerall = !numhelper(2100)

triggerall = root,movetype != H

triggerall = root,stateno != [120,155]

trigger1 = (root,power >= 500 && root,movetype = A) || root,ctrl

trigger1 = (root,command = "c") && !(root,command = "holdfwd" && root,command = "c") && !(root,command = "holdback" && root,command = "c") && !(root,command = "holddown" && root,command = "c") && !(root,command = "Burst")

ID = 2100

name = "Yuki"

sprpriority = 4

pos = ceil(p2dist X)-960,ceil(p2dist Y)-510

postype = P1

facing = 1

stateno = 2100

keyctrl = 0

ownpal = 0

size.xscale = 1

size.yscale = 1

[State 2090, Mikuru Call]

type = PlaySnd

triggerall = !numhelper(2200)

triggerall = root,movetype != H

triggerall = root,stateno != [120,155]

trigger1 = root,power >= 500 && root,movetype = A || root,ctrl

trigger1 = (root,command = "c" && root,command = "holdfwd")

value = 11,30

[State 2090, Mikuru Meter]

type = explod

trigger1 = (NumExplod(11101) = 0)

anim = 11100

id = 11101

postype = left

pos = ifelse(TeamSide = 2,203,76),34

facing = ifelse(teamside = 1,1,1)

vfacing = -1

ontop = 0

sprpriority = 5

supermovetime = 99999

pausemovetime = 99999

removetime = -1

bindtime = -1

removeongethit = 0

ownpal = 1

ignorehitpause = 1

scale = 0.44,0.78

[State 3102, Mikuru Meter Status]

type = ModifyExplod

triggerall = numhelper(2200)

trigger1 = root,fvar(8)

ID = 11101

scale = 0.00119+(root,fvar(8)/910),0.78

ignorehitpause = 1

[State 2090, Mikuru]

type = Helper

triggerall = !numhelper(2200)

triggerall = root,movetype != H

triggerall = root,stateno != [120,155]

trigger1 = root,power >= 500 && root,movetype = A || root,ctrl

trigger1 = (root,command = "c" && root,command = "holdfwd")

ID = 2200

name = "Mikuru"

sprpriority = 1

pos = -300,0

postype = P1

facing = 1

stateno = 2200

keyctrl = 0

ownpal = 0

size.xscale = 1

size.yscale = 1

[State 2090, Kyon Meter]

type = explod

triggerall = (NumExplod(11102) = 0)

trigger1 = root,fvar(1) < 1350

anim = 11100

id = 11102

postype = left

pos = ifelse(TeamSide = 2,225,100),57

facing = ifelse(teamside = 1,1,1)

vfacing = -1

ontop = 0

sprpriority = 5

supermovetime = 99999

pausemovetime = 99999

removetime = -1

bindtime = -1

removeongethit = 0

ownpal = 1

ignorehitpause = 1

scale = 0,0.78

[State 3102, Kyon Meter Status]

type = ModifyExplod

triggerall = NumExplod(11102)

trigger1 = root,fvar(1)

ID = 11102

scale = 0.44*((root,fvar(1))*0.0006),0.78

ignorehitpause = 1

[State 3102, Kyon Meter End]

type = RemoveExplod

trigger1 = numhelper(2300)

id = 11102

ignorehitpause = 1

[State 2090, Kyon Meter 2]

type = explod

triggerall = (NumExplod(11103) = 0)

trigger1 = numhelper(2300)

anim = 11100

id = 11103

postype = left

pos = ifelse(TeamSide = 2,225,99),57

facing = ifelse(teamside = 1,1,1)

vfacing = -1

ontop = 0

sprpriority = 5

supermovetime = 99999

pausemovetime = 99999

removetime = -1

bindtime = -1

removeongethit = 0

ownpal = 1

ignorehitpause = 1

scale = 0.43,0.77

[State 3102, Kyon Meter Status 2]

type = ModifyExplod

triggerall = NumExplod(11103)

triggerall = numhelper(2300)

trigger1 = helper(2300),fvar(2)

ID = 11103

scale = 0.43-((helper(2300),fvar(2))*0.00043),0.77

ignorehitpause = 1

[State 3102, Kyon Meter End]

type = RemoveExplod

triggerall = numhelper(2300)

trigger1 = helper(2300),fvar(2) >= 1000

id = 11103

ignorehitpause = 1

[State 2090, Kyon Call]

type = PlaySnd

triggerall = root,fvar(1) < 1530

triggerall = !numexplod(10020)

trigger1 = (root,command = "c" && root,command = "holdback") && root,ctrl

value = 11,28

[State 2090, Kyon Call]

type = Explod

triggerall = root,fvar(1) < 1530

triggerall = !numexplod(10020)

trigger1 = (root,command = "c" && root,command = "holdback") && root,ctrl

anim = 10020

ID = 10020

postype = p1

removetime = -2

bindtime = -1

pos = 30,-90

scale = 0.5,0.5

ignorehitpause = 1

[State 2090, Kyon]

type = Helper

triggerall = root,fvar(1) >= 1530

triggerall = !numhelper(2300)

trigger1 = root,movetype != H

trigger1 = root,stateno != [120,155]

ID = 2300

name = "Kyon"

sprpriority = 1

pos = 0,0

postype = P1

facing = 1

stateno = 2300

keyctrl = 0

ownpal = 0

size.xscale = 1

size.yscale = 1

[State 2090, Damage Scaling]

type = parentvarset

trigger1 = projhit2200 = 1

trigger1 = !moveguarded

fvar(4) = fvar(4)*0.94

ignorehitpause = 1

persistent = 0

[State 2090, End]

type = DestroySelf

trigger1 = WinKO

trigger2 = Lose

This is the helper that remains for the entire round and is only present after intros and before win/lose states. This helper is used to call forth and monitor all assists, therefore, it's a helper that also calls in other helpers.

Spoiler, click to toggle visibilty

; Kyon

[Statedef 2300]

type = S

movetype = I

physics = S

ctrl = 0

velset = 0,0

anim = 1

sprpriority = -1

[State 2300, Playsnd]

type = playsnd

trigger1 = time = 10

value = 10,0

[State 2300, Kyon's Life]

type = varset

trigger1 = 1

fvar(2) = 0

ignorehitpause = 1

[State 2300, Angledraw]

type = angledraw

trigger1 = 1

scale = 1.1,1.1

ignorehitpause = 1

[State 2300, Posset]

type = posset

trigger1 = 1

y = 3

[State 2300, Invuln]

type = nothitby

trigger1 = 1

value = SCA

time = -1

[State 2300, Port]

type = Explod

trigger1 = time = 6

anim = 10050

postype = Left

removetime = -2

bindtime = -1

ontop = 1

pos = 160,110

scale = 1,1

pausemovetime = 9999

supermovetime = 9999

ignorehitpause = 1

[State 2300, Pause]

type = pause

trigger1 = time = 6

time = 120

movetime = 0

[State 2300, Changeanim]

type = changeanim

trigger1 = time = 9

value = 9205

persistent = 0

[state 2203, Fade]

type = Trans

trigger1 = Time > 8

trans = addalpha

alpha = time, 256-(time*2)

persistent = 1

[State 2300, End]

type = Changestate

triggerall = ishelper

trigger1 = time = 180

value = 2310

;---------------------------------------------------------------------------

[Statedef 2310]

type = S

movetype = I

physics = N

ctrl = 0

sprpriority = -1

[State 2310, Kyon's Life]

type = varadd

trigger1 = 1

fvar(2) = gethitvar(damage)

ignorehitpause = 1

[State 2310, Invuln]

type = nothitby

trigger1 = 1

value = ,at

time = -1

[State 2310, Angledraw]

type = angledraw

trigger1 = 1

scale = 1.1,1.1

[State 2310, Turn]

type = turn

trigger1 = facing != root,facing

[State 2310, Velset]

type = Velset

trigger1 = rootdist x > 30

x = const(velocity.walk.fwd.x)

[State 2310, Velset]

type = Velset

trigger1 = rootdist x < 30

x = const(velocity.walk.back.x)

[State 2320, Velset]

type = Velset

trigger1 = rootdist x = [-30,30]

x = 0

[State 2310, Changeanim]

type = changeanim

trigger1 = rootdist x = [-30,30]

value = 9210

persistent = 83

elem = 5

[State 2310, Changeanim]

type = changeanim

trigger1 = rootdist x != [-30,30]

value = 9220

persistent = 57

[State 2310, Posset]

type = posset

trigger1 = 1

y = 3

[State 2310, End]

type = Changestate

triggerall = ishelper

trigger1 = time = 240

value = 2340

[State 2310, End]

type = Changestate

triggerall = ishelper

trigger1 = fvar(2) >= 1000

value = 2350

[State 2310, Hitoverride]

type = hitoverride

trigger1 = stateno != 5000

attr = SCA,AT,AA,AP

slot = 0

stateno = Cond((fvar(2) >= 1000),2350,2320)

time = -1

[State 2310, End]

type = Changestate

triggerall = ishelper

trigger1 = root,win

value = 2360

[State 2310, End]

type = Changestate

triggerall = ishelper

trigger1 = root,lose

trigger2 = drawgame

value = 2375

;---------------------------------------------------------------------------

[Statedef 2320]

type = S

movetype = I

physics = N

ctrl = 0

velset = 0,0

anim = 9230

sprpriority = -1

[State 2320, Playsnd]

type = playsnd

trigger1 = time = 0

value = 10,1

[State 2320, Kyon's Life]

type = varadd

trigger1 = 1

fvar(2) = gethitvar(damage)

ignorehitpause = 1

[State 2320, Invuln]

type = nothitby

trigger1 = 1

value = ,at

time = -1

[State 2320, Hitoverride]

type = hitoverride

trigger1 = 1

attr = SCA,AT,AA,AP

slot = 0

stateno = Cond((fvar(2) >= 1000),2350,2320)

time = -1

[State 2320, Angledraw]

type = angledraw

trigger1 = 1

scale = 1.1,1.1

ignorehitpause = 1

[State 2320, Velset]

type = Velset

trigger1 = time = 0

x = -1

[State 2320, Posset]

type = posset

trigger1 = 1

y = 3

[State 2320, End]

type = Changestate

triggerall = ishelper

trigger1 = animtime = 0

value = 2310

;---------------------------------------------------------------------------

[Statedef 2340]

type = S

movetype = A

physics = N

ctrl = 0

velset = 0,0

anim = 9240

sprpriority = -1

[State 2340, Guard Break]

type = TargetState

trigger1 = root,var(11) >= 1000

value = 5400

ignorehitpause = 1

[State 2340, Kyon's Life]

type = varadd

trigger1 = 1

fvar(2) = gethitvar(damage)

ignorehitpause = 1

[State 2340, Invuln]

type = nothitby

trigger1 = 1

value = ,at

time = -1

[State 2340, Playsnd]

type = playsnd

trigger1 = animelem = 2

value = 10,3

[State 2340, Hitoverride]

type = hitoverride

trigger1 = 1

attr = SCA,AT,AA,AP

slot = 0

stateno = Cond((fvar(2) >= 1000),2350,2320)

time = -1

[State 2340, Angledraw]

type = angledraw

trigger1 = 1

scale = 1.1,1.1

ignorehitpause = 1

[State 2320, Velset]

type = Velset

trigger1 = animelem = 2

x = floor(p2dist x /12)

[State 2320, Velset]

type = Velset

trigger1 = animelem = 3

x = floor(p2dist x /25)

[State 2340, Velset]

type = velset

trigger1 = p2dist x < 5

x = 0.1

[State 2340, Posset]

type = posset

trigger1 = 1

y = 3

[State 3240, Playsnd]

type = PlaySnd

trigger1 = AnimElem = 2

value = 0,5

volumescale = 255

[State 2340, Counter Hit Bonus]

type = TargetLifeAdd

trigger1 = root,var(56) = 1

value = ceil(-30)

ignorehitpause = 1

[State 2340, 1]

type = HitDef

trigger1 = animelem = 2

trigger2 = animelem = 3

attr = S, NA

animtype = Hard

damage = ceil(30*root,fvar(4)),10

getpower = 75,75

givepower = 30,30

hitflag = MAF

guardflag = HA

priority = 4, Hit

pausetime = 12,27

guard.pausetime = 10,20

sparkno = s6102

guard.sparkno = S6120

sparkxy = -10,-50

hitsound = S1,9

guardsound = S2,1

ground.type = High

ground.slidetime = 12

ground.hittime = 24

ground.velocity = -6

guard.velocity = -5

guard.ctrltime = 20

air.velocity = -6,-9

air.fall = 1

fall.recover = 0

[State 3240, Counter Hit/First Attack Flag]

type = Explod

triggerall = !numexplod(9999)

trigger1 = movehit = 1

anim = 1

ID = 9999

postype = left

removetime = 22

pos = 999999,999999

[State 3240, Guard Crush Flag]

type = projectile

trigger1 = moveguarded

projID = 9999

projanim = 1

projremovetime = 30

ignorehitpause = 1

[State 2340, End]

type = Changestate

triggerall = ishelper

trigger1 = animtime = 0

value = 2310

;---------------------------------------------------------------------------

[Statedef 2350]

type = S

movetype = I

physics = N

ctrl = 0

velset = -6,-4

anim = 9270

sprpriority = -3

[State 2350, Playsnd]

type = playsnd

trigger1 = time = 0

value = 10,4

[State 2350, Angledraw]

type = angledraw

trigger1 = 1

scale = 1.1,1.1

ignorehitpause = 1

[state 2350, Fade]

type = Trans

trigger1 = Time > 30

trans = addalpha

alpha = 256-(time*2),256

persistent = 1

[State 2350, Invuln]

type = nothitby

trigger1 = 1

value = ,at

time = -1

[State 2350, End]

type = DestroySelf

triggerall = ishelper

trigger1 = time = 128

;---------------------------------------------------------------------------

[Statedef 2360]

type = S

movetype = I

physics = S

ctrl = 0

velset = 0,0

sprpriority = -3

[State 2360, Playsnd]

type = playsnd

trigger1 = time = 90

value = 10,5

[State 2360, Invuln]

type = nothitby

trigger1 = 1

value = ,at

time = -1

[State 2360, Angledraw]

type = angledraw

trigger1 = 1

scale = 1.1,1.1

ignorehitpause = 1

[State 2360, Velset]

type = Velset

trigger1 = 1

x = 0

y = 0

[State 2360, Posset]

type = posset

trigger1 = 1

y = 3

[State 2360, Changeanim]

type = changeanim

trigger1 = time = 75

value = 9260

persistent = 0

;---------------------------------------------------------------------------

[Statedef 2375]

type = S

movetype = I

physics = S

ctrl = 0

velset = 0,0

sprpriority = -3

[State 2375, Playsnd]

type = playsnd

trigger1 = time = 60

value = 10,2

[State 2375, Invuln]

type = nothitby

trigger1 = 1

value = ,at

time = -1

[State 2375, Angledraw]

type = angledraw

trigger1 = 1

scale = 1.1,1.1

ignorehitpause = 1

[State 2375, Velset]

type = Velset

trigger1 = 1

x = 0

y = 0

[State 2375, Posset]

type = posset

trigger1 = 1

y = 3

[State 2375, Changeanim]

type = changeanim

trigger1 = time = 75

value = 9250

persistent = 0

These are all states for Kyon himself (the assist helper that is the topic of this thread).

Spoiler, click to toggle visibilty

[State -2, Striker System]

type = Helper

triggerall = numhelper(2090) < 1

trigger1 = roundstate = 2

trigger1 = numenemy && enemy,life > 0

ID = 2090

name = "SOS Assists"

sprpriority = 4

pos = 0,0

postype = P1

facing = 1

stateno = 2090

keyctrl = 0

ownpal = 1

size.xscale = 1

size.yscale = 1

[State -2, Kyon Set]

type = varset

trigger1 = roundstate = 0

trigger2 = numhelper(2300)

trigger2 = helper(2300),fvar(2) >= 1000

trigger3 = fvar(1) < 0

fvar(1) = 0

ignorehitpause = 1

[State -2, Kyon Set]

type = varadd

triggerall = fvar(1) < 1531

triggerall = numhelper(2090)

trigger1 = helper(2090),numexplod(10020)

fvar(1) = 1

ignorehitpause = 1

[State -2, Kyon Set]

type = varadd

triggerall = fvar(1) < 1530 && fvar(1) > 0

trigger1 = movetype = H && StateNo != [120,155]

fvar(1) = -3

ignorehitpause = 1

All the statedef -2 stuff for the Kyon assist as well as what calls in the helper that monitors all assists.

This is actually my first time making assists lol.