Oyaminartok, Polar Werebear

Oyaminartok, Polar Werebear has Hexproof if it
hasn't dealt damage yet.
Whenever Oyaminartok deals combat damage to
a player, create a Food token.
{u}, Sacrifice a Food: Draft a card from
Oyaminartok's spellbook.
When you do, add {u}{u}{u}. Spend this mana only
to cast blue creature spells.