Biomorph

Mimics possess the ability to shapeshift by manipulating amorphous muscle tissues and reallocating stored biomass to generate new structures. While their hardened faux-wood shell cannot warp, mimics can reshape their underside and "jaw" to form new body parts. To replicate an object or creature, the mimic must be familiar with its basic structure and function. For example, a mimic can learn to form an ear or other organic structure if it has consumed enough of the necessary material.

Shapeshifting sometimes requires more mass than the mimic can initially support. To compensate, mimics stockpile biomass through consumption, which is then used to fuel transformations. If the mimic loses biomass (e.g., if severed), it disintegrates, preventing infinite passive healing. Your stockpile increases upon every creature consumed due to your Biomass Storage trait.

Your DM may determine how many attempts it takes for a mimic to successfully replicate a body part's function. A skill check may be required for the first attempt to gauge progress. Mastery of a mimic's transformations is determined by the DM.