You are forced to add 1 to one ability scores, and subtract 1 on another.

Beginning at first level, you may mutate your body to form one bodily feature 10 times per long rest, which can make one natural weapon out of bone and flesh that is non-magical (such as a large mutated bone as a club, or a splintered bone as a dagger) although it remains attached to you, and will rot away in one hour if removed from you, and can be broken if aimed for (the weapon has its own hp equal to 4 + your CON modifier). You can also choose to mutate a bony structure that awards you temporary hitpoints (equal to 10 + CON), and will grant you +1 to AC while the structure is intact (still has temp hitpoints left). You may also form a mouth (takes 3 charges to form) that gives access to a grapple attack, which acts as an unarmed strike that grapples the target, with a DEX save (DC 8 + Player DEX) to avoid, and when grappled, a STR save (DC 8 + Player STR) to break free. While gripped on a target, the mouth will produce digestive acids, breaking down the target in order to be edible. While grappled, a target takes 1d4 acid damage at the start and end of every turn they take. 

Upon taking cold or fire damage however, this ability is blocked for your next turn. Additionally, being in a cold environment for over 1 hour will half all movement if not accounted for.

Beginning at 4th level, Every time you get attacked by a melee weapon, the attacker must make a DC 16 CON save, and on fail, will take 1 acid damage, and none on a success.

Beginning at 10th level, You gain access to 2 transmutation level 2 or under spells of your choice.