Shipwreck Marsh enters tapped unless you control two or more other lands. {T}: Add {U} or {B}.
Tangled Colony can't block. When Tangled Colony dies, create X 1/1 black Rat creature tokens with "This creature can't block," where X is the amount of damage dealt to it this turn.
Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield. {3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)
{T}: Add {C}. {T}: Add {U} or {B}. Underground River deals 1 damage to you.
Whenever Ayara, First of Locthwain or another black creature you control enters, each opponent loses 1 life and you gain 1 life. {T}, Sacrifice another black creature: Draw a card.
Morphic Pool enters tapped unless you have two or more opponents. {T}: Add {U} or {B}.
As an additional cost to cast this spell, pay X life. All creatures get -X/-X until end of turn.
Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep. You draw a card at the beginning of the next turn's upkeep.