Bag of the Terror Lizard

It looks like an ordinary bag and weighs 1/2 lb. Inside each bag is a large scale the size of human palm, and has strange glowing runes. You can use a bonus action to call out the command word to consume the scale and summon a Ravasaur anywhere inside unoccupied space 20 ft from you. It will disappear when it's hit points reach 0 or at dawn. The scale returns to the bag at dawn. The Ravasaur can understand you, but cannot communicate directly with you.  It will listen to your commands as best as it can and moves on your turn.  Ravasaur stats below. 

Ravasaur

Large beast, neutral

Armor Class 16 (Natural armor)

Hit points 50 (8d10+10)

Speed 45 ft

Skills Perception +4

Senses passive Perception 14

Languages Ravasaur-ish

Challenge 2(450 XP)

Pack Tactics. Ravasuars have advantage on attacks if they are within 10ft of another ravasaur.

Lethal Venom. Targets that a venomhide ravasaur hits with either attack must make a DC 18 Constitution check or take 1d4+2 poison damage at the start of every turn (or 6 seconds) for one minute. Cannot be reapplied.

Venomous Hide. Weapon attacks against a venomhide ravasaur have a chance to rub the venom off onto the weapon. This venom is ineffective against the same or other venomhide ravasaurs.

Actions

Multiattack. Ravasaurs make one attack with their claws, and one bite. The attacks must target the same enemy.

Bite. Melee weapon attack: +2 to hit, one target. Hit: 3d10+5 piercing damage.

Claws. Melee weapon attack: +2 to hit, one target. Hit: 2d10+5 slashing damage.

Notes: Summoning, Utility