Ancient Sentinel

If Ancient Sentinels toughness would drop below
one, it stays on the board. If its toughness is still
below one at the end of turn, put it in the
graveyard.

"After Millennia of guarding an ancient tomb, he
forgot who he was or why and what he was
guarding. Since no one ever came to plunder its tomb,
one day he sealed it and decided to discover the
outside world."