Spooky's REM Disorder

Spooky's REM Disorder enters the battlefield
with 1 "nightmare" counter attached to it.
During your endstep, flip a coin until either side
lands twice in a row, then add 1 nightmare
counter when you do. For each flip failed, you
lose 1 life.
{u}{b}, {t}: Remove 1 nightmare counter. Create a
1/1 black Regret creature token with "this
creature can't block, and is unblockable," it is a
Nightmare Illusion in addition to its other types.
These creatures die if this enchantment is exiled.