Bremen, the Eternal

Alchemy- Whenever you pay a Potion cost, you may exile Bremen, the Eternal, then return it to the battlefield.
When Bremen, the Eternal enters the battlefield, concoct, then create a legendary colorless artifact token named The Philosopher's Stone with, "Whenever a creature named Bremen, the Eternal is dealt damage, it gains persist until end of turn."
"'Forever' is not a word to say flippantly."