SCP-106, The Old Man

Whenever SCP-106 attacks, exile target creature defending player controls. At the beginning of the
next turn, return that creature to the battlefield
tapped with a -1/-1 counter on it.

Whenever another creature dies, you may pay {b}. If you do add a 1+/1+ counter on SCP-106


"The echoes of its victims reverberate through the
endless corridors of its domain."