Lost in a Nightmare

At the beginning of each player's upkeep, that
player loses 1 life and creates a 1/1 black Nightmare
Bird creature token with flying and "This creature
can't block."

Whenever one or more nightmares die, put a
memory counter on Lost in a Nightmare.

At the beginning of your end step, if Lost in a Nightmare has ten or more memory counters on it, sacrifice it and draw seven cards.