Bryyus The First, Liberator

Whenever Bryyus The First, Liberator enters the battlefield, search your library for a Cold-Blooded creature with mana value X or less.
(Basalisk, Crocodile, Dinosaur, Dragon, Drake,
Frog, Gorgon, Hellion, Hydra, Insect, Lizard, Reptilicus, Salamander, Serpent, Snake, Turtle,
Viashino and Wurm creatures are Cold-Blooded.)

Whenever Bryyus The First, Liberator attacks,
return it to its owners hand.