Parasite

These sneaky specters laugh at the idea of "You can't put a fire out from inside the house." They have been known to dive head first into the gullets of aggressive predators for the sole purpose of being a pest in their gut.

Stomach Parasite

At 3rd level, you gain resistance to Digestion Damage. Additionally, you are no longer considered restrained while bellied by a hostile creature.

Hidden Form

Starting at 3rd level, while Bellied by another creature, you may choose not to leave a visible impression on the outside of the predator. You still take up space within their stomach.

Stealth Entry

Also starting at 3rd level, you may enter or exit a willing creature's stomach using 5 feet of movement. Additionally, you may make Sneak Attacks as normal while inside of a willing creature, and you are not blinded or restrained. If you are currently in or have exited a creature this turn, you don’t need advantage on the attack roll to use your Sneak Attack as long as you don’t have disadvantage on the attack roll. All the other rules for Sneak Attack still apply to you.

Invasion

Starting at 9th level, you may use 5 feet of movement to enter or exit an unwilling creature. When entering, make a Dexterity(Stealth) check vs the creature's passive perception. On a success, you become bellied by the pred, and you are not blinded or restrained. On a fail, the creature may attempt to Devour you as a reaction. All attacks made on a creature from within their own stomach while you aren't restrained are made with Advantage.

Greater Parasite

Starting at 13th level, you can choose a number of Digestion Dice applied to you equal to your Proficiency Modifier. The chosen Dice have their values halved, rounding down. 1s cannot be rounded down to 0s in this way.

Master Parasite

Starting at 17th level, creatures cannot regurgitate you without your permission, and you may exit a willing creature's stomach on your turn without expending any movement.