Akawalli, the Seething Tower

Descend 4 — As long as there are four or
more permanent cards in your graveyard,
Akawalli, the Seething Tower gets +2/+2
and has trample.
Descend 8 — As long as there are eight or
more permanent cards in your graveyard,
Akawalli gets an additional +2/+2 and can't
be blocked by more than one creature.