Have

Urza's Incubator

As Urza's Incubator enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Up to one target creature gets -1/-1 until end of turn. You create a 1/1 black Rat creature token with "This creature can't block."

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Search your library for a card, put that card into your hand, then shuffle.

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

{1}{B}, Pay 2 life: Return target creature card from your graveyard to your hand.

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

{T}, Sacrifice Rat in the Hat: Until end of turn, you may cast target creature card that has a hat from your graveyard.