Stefan, Dreadful Collector

Intimidate, Menace
Whenever another Creature you control leaves
the battlefield, put a +1/+1 counter on Stefan, Dreadful Collector.
Counters remain on Stefan, as it moves to any
zone other than player`s library.
At the beginning of your end step, when Stefan
is on the battlefield, half all counters on Stefan,
unless you pay an amount of {p/b} equal to
the number of counters plus one on Stefan.