Clattering Skeletons

When Clattering Skeletons dies, venture into the dungeon. (Enter the first room or advance to the next room.)

Skeletal Swarming

Each Skeleton you control has trample, attacks each combat if able, and gets +X/+0, where X is the number of other Skeletons you control.
At the beginning of your end step, create a tapped 1/1 black Skeleton creature token. If a creature died this turn, create two of those tokens instead.

Bone Dragon

Flying
{3}{B}{B}, Exile seven other cards from your graveyard: Return Bone Dragon from your graveyard to the battlefield tapped.

Sanitarium Skeleton

{2}{B}: Return Sanitarium Skeleton from your graveyard to your hand.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Disfigure

Target creature gets -2/-2 until end of turn.

Jungle Hollow

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {G}.

Murder

Forest

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Death-Priest of Myrkul

Skeletons, Vampires, and Zombies you control get +1/+1.
At the beginning of your end step, if a creature died this turn, you may pay {1}. If you do, create a 1/1 black Skeleton creature token.