Carcinus, Soul Pincher

When a Crab you control deals combat damage to a player, that player mills cards equal to the highest toughness among the permanents you control.

At the beginning of your Upkeep, if you both own and control Carcinus, Soul Pincher and an enchantment named Heart of the Ocean, exile them, then meld them into Karkinos, Zendikar's Hydrosoul.