Blighted Roberts, Evil Consort

Whenever Blighted Roberts, Evil Consort enters
the battlefield, if you don’t control a creature
named Vesper, create Vesper, a legendary 2/1
blue and black Bat creature token with
Whenever a creature you control mutates, you
can play one permanent card from your
graveyard.
{2}{u/b}{t}— Create a token copy of one mutated creature you control with haste. Sacrifice this
creature at the next end step.