Decimator beetle

When Decimator Beetle enters the battlefield,
put a -1/-1 counter on target creature you
control.
Whenever Decimator Beetle attacks, remove
a -1/-1 counter from target creature you control
and put a -1/-1 counter on up to one target
creature defending player controls.
An unstoppable tank of an insect, Seltas queens are
well known for being living juggernauts.