The stone-skin potion is a magic potion that causes the drinker to grow hard, rock-like armor on their skin. This spell is useful for self-defense, but can have side effects if overused.
The potion has a slight purplish blue color, and it is stored in a small bottle.
The stone-skin potion is a magical body enhancement potion that allows the drinker to grow strong stone-like armor on their skin. The exact size and strength of the armor is determined by how much the user drinks. It is unclear how to find the potion or what the ingredients are. However, Finn, who has no magical skill or knowledge, managed to get it in great amounts, implying that the potion is easy to come by. Even though the potion is beneficial for self-defense, it can have dangerous side effects if the user drinks too much. This is shown when the town cobbler's hands got too big to do his job. It appears that a skilled doctor can undo harmful effects, as the cobbler went to one to have the effects undone.
When Billy tells Finn and Jake to give up, they try to be help out in other ways. They make gruel to give to the townspeople, but unbeknownst to Jake, Finn put the stone-skin potion in it. He finds out when the townspeople start changing into rock-like creatures. Jake asks Finn how much potion he put in the gruel, with Finn revealing several empty bottles. The town cobbler could no longer do his job, forcing Finn and Jake to man his shop while he went to the doctor.
- The stone-skin potion may be based on a spell of the same name used in many role-playing games. Its earliest usage is probably in Dungeons & Dragons. It is described in this example.
- The stone-skin potion is used as a upgrade in Candy Scramble.