Warlock, Phalanx Outcast

Hangarback Walker enters the battlefield with X
+1/+1 counters on it.
When Hangarback Walker dies, create a 1/1
colorless Thopter artifact creature token with
flying for each +1/+1 counter on Hangarback
Walker.
{1},{t}: Put a +1/+1 counter on Hangarback
Walker.