The Mouse

When this creature enters the battlefield, target opponent creates a 3/1 red Fox creature token, target opponent creates a 1/1 blue Bird creature token with flying, and a 1/2 black Snake creature with deathtouch.
As long as your opponents control a Fox, a Bird, and a Snake, The Mouse gets +1/+1, lifelink, and indestructible.

A mouse took a stroll through the deep dark wood...