Valen, Rogue of Dust

Valen, Rogue of Dust enters the battlefield with
X +1/+1 counters on it, where X is the number
of Dust creature tokens you control, then create
a number of 1/1 Dust creature tokens equal to
Valen's power.
{4}{r}, {t}: Exile Valen, then return him to the battlefield under his owner's control.
Dust creatures you control have "{4}{u}: This
creature becomes a copy of target creature.
Sacrifice it at the end of this turn."