msem-instigator

Look at the top two cards of your library. Put one of them into your hand, then submerge the other. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Whenever a player casts an instant or sorcery spell that targets exactly one creature they don't control, you may copy that spell. If you do, you may choose new targets for the copy.

Submerge each creature you control. At the beginning of the next end step, you may turn any number of face down creatures you control face up. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Look at the top four cards of your library. You may reveal a noncreature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Put target nonland permanent on top of its owner's library. If you control a Wizard, you may put that permanent on the bottom of its owner's library instead.

Exile target creature. Return that card to its owner's hand at the beginning of its owner's next end step.

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Hexproof
Whenever another creature you control becomes the target of a spell an opponent controls, you may submerge that creature. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)
{1}{U}{U}: Turn target face-down creature you control face up.

When Isle Conservator enters, if you control a legendary creature, submerge target creature an opponent controls. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

When Keeper of Blue Incense enters, submerge target card from your graveyard. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Submerge target spell. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Lumbering Stoneshell has hexproof as long as it's untapped.

Counter target spell unless its controller pays {3}. That spell's controller mills three cards.

Tap up to two target creatures an opponent controls. Those creatures don't untap during their controller's next untap step.
Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, you may switch Master of Tranquility's power and toughness until end of turn.

Flying
When Mother of Owls dies, you may return target creature an opponent controls to its owner's hand.

Look at the top three cards of your library, then put them into your graveyard or back on top of your library in any order.
Draw two cards.

Counter target noncreature spell.

Counter target instant or sorcery spell unless its controller pays {3}.

Draw three cards. If you control a Wizard, untap up to three lands.

When Obscure Apostle enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Whenever you sacrifice an Idol, Obscure Apostle can't be blocked this turn.

Flying
Whenever an opponent casts a spell, counter it unless that player pays {1} for each spell cast before it this turn.

When Peddler of Commonwares enters, you may draw a card. If you do, discard a card.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast an instant or sorcery spell, up to one other target creature has base power and toughness 0/2 until end of turn.

Trample
When Shigurei, the Floodbringer enters, up to three target permanents become colorless Island lands.