Agate Instigator is a rare Creature — Lizard Rogue card from Bloomburrow Commander (BLC), collector number 21. Current market price: $7.89, TCGplayer market prices via Scryfall.
Offspring {1}{R} (You may pay an additional {1}{R} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.) Whenever another creature you control enters, this creature deals 1 damage to each opponent.