Tick, Tock

When Tick, Tock enters the battlefield, Create a 0/1 colorless human creature token with "Other creatures you control gain hexproof."
At the beginning of each upkeep, if more than 5 upkeeps have passed since Tick, Tock entered the battlefield, sacrifice it and destroy all creatures.
{5}: Exile Tick, Tock, then return it to the battlefield, your opponents may activate this ability at any time.