Carcinization

Carcinization is a natural process and cannot
be countered
All creatures on the battlefield are now 3/3
blue Crabs. For each creature that would
become a crab, that player's controller may
discard a card. If they discard a card, that
creature is unaffected by Carcinization.
All creatures which are now crabs must
be inverted.
Carcinization, uh, finds a way