Simic Shellback

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
As long as you control another multicolored creature, Simic Shellback has deathtouch.
Momir Vig teaches that some of the Simic's creations benefit from post-breeding exposure to even more varied mutant beasts.