Skittering Crustacean is a common Creature — Crab card from Treasure Chest (PZ2), collector number 65777.
{6}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.) As long as this creature is monstrous, it has hexproof. (It can't be the target of spells or abilities your opponents control.)