Adaptive Skin: While in dim light, the mimic can take the Hide action as a bonus action.

Arms Mimic: The mimic can transform its pseudopods into any simple melee weapon as a bonus action. The weapon it creates are as hard as the finest steel. The mimic has proficiency on any weapon it mimics and has a reach of 10ft. regardless of weapon.

Spider Mimic: The mimic can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Multiattack: The mimic can make two pseudopod or weapon attacks.

Pseudopod: Melee Weapon Attack: +3 to hit, reach 10 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage.

Sickle: Melee Weapon Attack: +3 to hit, reach 10 ft., one target. Hit: 4 (1d6 + 1) piercing damage.

Subsume: The mimic destroys one nonmagical or nonadamantine object of Tiny size within 5 feet. The head of a unconscious, dead, or paralyzed Humanoid or Beast within 5 feet can also be the target, destroying the head and killing the creature.

Aberrant Shape-Shift: The mimic shape-shifts to resemble a Tiny object while retaining its game statistics, or it returns to its true blob form. This must be an objects it had destroyed using its Subsume. Any equipment it is wearing or carrying isn't transformed.

Aberrant Connection: Alternatively, the mimic shape-shifts to resemble the head it has destroyed using its Subsume action. If the body of the creature is within 5 feet and has been dead for no more than 1 round, the mimic may replace itself as the head of the creature. The mimic now controls the body. The mimic now controls the body. The mimic may then use its bonus action to command the creature's body, using the statistics it had in life. 

The body is treated as a separate creature with 10 hit points and an AC of 10, and the body is destroyed if it is reduced to 0 rendering it useless. The connection lasts until the body drops to 0 Hit Points or the mimic leaves as a Bonus Action. When the connection ends, the mimic appears in an unoccupied space within 5 feet of the body, and the body unable to be controlled in this manner again.

The mimic has the digested creature's memories and behaves like that creature, but with occasional lapses. An observer familiar with the digested creature can recognize the discrepancies with a successful DC 20 Wisdom (Insight) check, or automatically if the mimic does something in direct contradiction to the digested creature's established beliefs or behavior.