Viper Tobi-Kadachi's size is 15ft by 15ft

Viper Tobi-Kadachi's ac is 20 while flying

Spots to hit: head, neck(slash/bludgeon), forelegs(slash/bludgeon)
Spots to miss: torso, tail, hind-legs
Vunerabilitys: thunder/lightning
Resistances: fire, necrotic
Immunitys: acid

Multi Attack: Viper Tobi-Kadachi makes 3 Needle Fire attacks.

Sweep: dc 16 dex save, 15ft range, one target
 hit: 24 (4d6+10) slashing damage, 40 (5d12+7) poison damage. target
 contracts noxious poison.

Charge: +13 to hit, move 15ft forward,
 hit: 35 (8d6+7) bludgeoning damage, target is knocked back/prone 10ft. dc 13 con save or be stunned for 2 rounds.

Tail Whip: +13 to hit, 10ft range, one target
 hit: 25 (5d6+7) bludgeoning damage, 33 (4d12+7) poison damage, target is knocked prone and stunned for 1 round.

Headbutt: +13 to hit, 5ft range, one target
 hit: 28 (6d6+7) bludgeoning damage, target must make a dc 19 con save or be paralyzed for 1 minute.

Needle Fire: +16 to hit, 20ft 180*,
 hit: 46 (6d12+7) poison damage, targets contract noxious poison, and flinch.

Jumping Slash: Viper Tobi-Kadachi jumps into the air, diving forward 10-15ft, and makes a Sweep attack with advantage. targets are knocked back/prone 20ft.

while flying: move an extra 10ft every attack.
Flying Sweep: dc 22 dex save, 20ft range, 15ft 90*,
 hit: 24 (4d6+10) slashing damage, 40 (5d12+7) poison damage. target contracts noxious poison, and flinches.

Ram: +13 to hit, 10ft range, one target
 hit: 28 (6d6+7) bludgeoning damage, target must make a dc 19 con save or be paralyzed for 1 minute.

Flying Needles: +16 to hit, 30ft 180*,
 hit: 73 (9d12+14) poison damage, targets contract noxious poison, flinch are knocked back/prone 10ft.

Dive: dc 19 dex save, 10ft range, move 20ft
 hit: 46 (7d8+14) bludgeoning damage, targets are knocked prone/back 15ft, and must make a dc15con save or be paralyzed for 1 minute.