Merfolk Assassin

Trample This creature enters tapped and doesn't untap during your untap step. At the beginning of your upkeep, you may sacrifice two Islands. If you do, untap this creature. This creature can't attack unless you sacrifice two Islands. (This cost is paid as attackers are declared.)

Disintegrate deals X damage to any target. If it's a creature, it can't be regenerated this turn, and if it would die this turn, exile it instead.

2, Discard a card at random: This enchantment deals 2 damage to any target.

2G, T, Discard two cards: All lands target player controls become 3/3 creatures until end of turn. They're still lands.

Mistform Ultimus is every creature type (even if this card isn't on the battlefield).

When this creature enters, sacrifice it unless you return three basic lands you control to their owner's hand. T, Return this creature to its owner's hand: Destroy target creature. It can't be regenerated. That creature's controller creates a 0/1 green Sheep creature token.

T: Draw a card and reveal it. If it isn't a land card, discard it.