Thrall, The Shaman

Hexproof. Whenever Thrall attacks, untap him.
At your upkeep, for each totem under your control, put a charge counter on Thrall. If Thrall have 3 or more charge counters, transform him.
{u},{t} Put a Manatide Totem token on the battlefield.
{r},{t} Put a Searing Totem token on the battlefield.
{g},{t} Put a Stoneclaw Totem token on the battlefield.