Charcoal Diamond enters the battlefield tapped. {T}: Add {B}.

Whenever one or more nontoken creatures you control die, investigate. This ability triggers only once each turn. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

{1}{B}: Return Reassembling Skeleton from your graveyard to the battlefield tapped.

As an additional cost to cast this spell, sacrifice an artifact or creature. Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Destroy target nonartifact creature.

Target creature gets -1/-1 until end of turn. Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.