The Horned Serpent

Menace, Trample, Deathtouch, Hexproof, Indestructible
This creatures power and toughness are equal to the total number of mana under your control.
{0}, create one 3/3 Special Tree creature token with Indestructible and Deathtouch.
{w}{w}{b}{b}{5}, destroy The Horned Serpent, search your library for one creature card of your choice.