Ants. Tiny.

Cost: 1.

Hero Action: If you are in Tiny hero form, exhaust Army of Ants → deal 1 damage to an enemy.

"Antvengers Assemble!" — Scott Lang
Dennis Medri
Ant-man #7. Ant-Man #9-11.
Army of Ants

This card is really, really strong. It's cheap, consistent damage, and you get three of them, and the damage over the course of the game you get from them is nuts. You're almost always going to be in Tiny hero form at some point on your turn, so even the "Tiny form" part of the cost is negligible.