Abandoned Incubator

When Abandoned Incubator enters the battlefield, target opponent reveals their hand
and discards a creature card at random. Then,
attach that card to Abandoned Incubator.
You may spend mana as if it were mana of any
type to cast the attached card. It is a black
Skeleton in addition to its other card types.
Whenever a card becomes unattached to
Abandoned Incubator, sacrifice it.