msem-instigator

Pelagic Hydra enters with seven +1/+1 counters on it.
{1}{G}: Put a +1/+1 counter on Pelagic Hydra.
Remove a +1/+1 counter from Pelagic Hydra: It deals 1 damage to target creature blocking or blocked by it.

Madness {4}{G} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Target creature gets +4/+4 until end of turn. Put a trample counter on it. If this spell's madness cost was paid, all creatures able to block that creature this turn do so.

Target player discards two cards. Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Exile target land. 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 a spell or ability with one or more targets is put onto the stack, reselect its targets at random.

When Pestilent Vermin enters, target opponent loses 2 life unless they discard a card.
Whenever you cast a Tale, you may return Pestilent Vermin from your graveyard to your hand.

When Petal Scatterer enters, create a green Aura enchantment token named Blossom attached to target land. It has enchant land and “Enchanted land has ‘{T}: Add {G}{G}.'”
Petal Scatterer gets +1/+1 for each noncreature, nonland permanent you control.

Enchant permanent
Enchanted permanent is a colorless Swamp Forest land.
Whenever enchanted permanent becomes tapped, its controller loses 1 life.

Target creature you control gets +2/+0 until end of turn. It fights target creature you don't control. (Each deals damage equal to its power to the other.)

Enchant creature you control
Enchanted creature has lifelink.
When Phantasmal Possession enters, exile target creature an opponent controls until Phantasmal Possession leaves the battlefield.

Return X target creature cards with mana value 3 or less from your graveyard to the battlefield, then choose one of them and exile the rest.

If a source would deal damage to you or a permanent you control this turn, prevent all but 1 of that damage.
Metamorph {1}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life unless that player is cursed.

Whenever Pillager's Sloop attacks, you may draw a card. If you do, discard a card.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Ship Vehicle becomes an artifact creature until end of turn.)

Destroy target creature with flying. You may put a land card from your hand onto the battlefield.

When Pious Flutist 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.”)

Enchant player
Whenever a creature enters under enchanted player's control, they lose 1 life.

When Pirate's Cutlass enters, attach it to target Pirate you control.
Equipped creature gets +2/+1.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

{T}: Add {C}.
{3}, {T}: Draw a card. Activate only if a creature died this turn.

Destroy target nonland permanent if its mana value is less than or equal to the number of colors among spells you've cast this turn.

Target opponent reveals their hand. You choose a creature card from it and exile that card.
Ferocious — If you control a creature with power 4 or greater, instead choose a nonland card from their hand and exile that card.

Whenever equipped creature attacks, each player loses 3 life.
Equip {2}

Trample, hexproof

This spell costs {1} less to cast if you cast a spell with a mana payment of exactly {U} this turn. The same is true for {R}.
Once each turn, when you cast a blue or red instant or sorcery spell with mana value 1, you may pay its mana cost. If you do, copy it. You may choose new targets for the copy.