Ancestral Memorium

When Ancestral Memorium enters the
battlefield, chose a creature type.
Whenever a creature you control of the
chosen type dies, you may exile it until Ancestral Memorium leaves the battlefield. If you do,
create a non creature artifact token copy of the
exiled creature. (it is not a creature)
If Ancestral Memorium would leave the battlefield, exile all tokens created by it, and
return all creatures exiled by it to their owner's graveyards.