msem-instigator

Flying
Whenever another creature dies, each opponent loses 1 life and you gain 1 life.

Trample
Creatures your opponents control get -1/-0.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
When Determined Koi has three or more +1/+1 counters on it, remove them all and transform it.

Menace
When Devious Kalku enters, you may search your library for a card, put that card into your graveyard, then shuffle.

Hexproof

Permanents you control gain indestructible until your next turn.
Fuse (You may cast one or both halves of this card from your hand.)

Hexproof

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.
Fabled {3}{R}{R} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Whenever you or a creature you control become the target of a spell or ability an opponent controls, that opponent gets a spite counter.

Scry X. (Then exile this card. You may cast the creature later from exile.)

Spells your opponents cast cost {1} more to cast.
Spells you cast cost {1} less to cast.

At the beginning of your end step, if you have no cards in hand, draw a card.
{2}{U}, {T}: Sacrifice any number of nontoken creatures. Create an X/X blue Horror creature token for each of those creatures, where X is the total power of those creatures.

Destroy target creature or planeswalker.
Fuse (You may cast one or both halves of this card from your hand.)

Whenever another creature dies, you gain 1 life.
At the beginning of each end step, if you gained 3 or more life this turn, transform Dowager of Traublassen.

Target creature gets +1/+3 and gains hexproof until end of turn. (Then exile this card. You may cast the creature later from exile.)

Flying
Ride {3}{U} ({3}{U}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Dramatic Peril deals damage equal to the number of lands you control to any target. (Cast a copy of this spell once while this creatures is on the battlefield.)

When Drop Bear enters, return another target permanent that isn't a land an opponent controls or a card in a graveyard to its owner's hand.

Defender
When Drunau Egg enters, target player mills two cards.
{3}{U}{U}: Transform Drunau Egg. Activate only as a sorcery and only if an opponent has thirteen or more cards in their graveyard.

Trample

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.

Tap target creature.
Fabled {3}{U} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Reach

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
When Eager Hatchling has three or more +1/+1 counters on it, remove them all and transform it.