Thirty seconds of almost-invulnerability and super-accelerated healing, then ten hours with no potions at all.
Carl slams it as Grull lifts his axe for a blow he knows will land close enough to kill him, with Protective Shell no help this time. The notification reads Gold-Standard! Your healing is super accelerated! and a thirty-second timer appears. Mordecai had prescribed exactly this for meeting a god — take the potion and run — and the cost is that Carl cannot take another potion for ten hours.
What the thirty seconds actually contain: the ground buckling and launching him into the air like a fiery catapult, a hard crunch against the wall of a train, a shockwave that shatters his back into hundreds of bits over and over while healing him each time, the god's flaming horseshoe pressing him into the ground and flattening his pelvis with his head missing the shoe's edge by inches, an unread achievement, and finally a rolling train car bowling right over him. He is healed through every one of them, and gets up when it ends.
Thirty seconds of being unkillable while a god destroys the ground around Carl.