Krobelus, Death Prophet

Whenever Krobelus enters the battlefield or
a non-Spirit creature dies, put a haunt counter
on Krobelus.
Whenever Krobelus attacks, remove all haunt
counters from it and create that many 1/1 black
Spirit creature tokens with flying and lifelink
that are tapped and attacking. At end of combat,
sacrifice each Spirit created this way, then put
a haunt counter on Krobelus for each Spirit
sacrificed this way.