Darkvision, it doesn’t need a description

The mimic adheres to anything that touches it. A Huge or smaller creature adhered to the mimic is also grappled by it (escape DC 13). Ability checks made to escape this grapple have disadvantage.

While the mimic remains motionless, it is indistinguishable from an ordinary object.

The mimic can use its action to polymorph into an object or back into its true, amorphous form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies. Since being awakened it can turn into a living creatire And it works just like a druids wild shape, only for objects and animals. At first level you can turn into anything of challenge rating 1/2 or less, fourth is 1 challenge rating, 6th and up is your level divided by three. You can use this trait three times per long rest for a living creature(undead and constructs are included in this classification, don’t try and cheat buckeroo) and at will for an object. You are restricted to one size class above you for what you can transform into.

your movement speed in the new form is half of its regular speed since you aren’t used to its limbs or other ways of moving, your speed is 20 if this would put your speed below your normal speed

The mimic has advantage on attack rolls against any creature grappled by it.

You start with common and one language your awakener knew (if they knew more then one)

Bite. Melee Weapon Attack: plus your  proficiency modifier and your strength modifier to hit plus your strength modifier to damage(piercing not poison), reach 5 ft., 1d6 piercing damage plus 1d4 acid damage. This increases to 1d8 piercing damage and 1d6 poison damage at level 4 and 1d8 poison damage is at level 6

Psuedopod. Melee Weapon Attack:  plus your  proficiency modifier and your strength modifier to hit plus your strength modifier to damage, reach 5 ft., one target. 1d8  bludgeoning damage. If you are in object form, the target is subjected to its Adhesive trait.

These are your immunities, what are you not getting about that?

you have immunity to acid damage

You get +2 to strength and +1 to constitution, It was too difficult for me to add these in to auto add themselves to your stat block so you’ll have to do it manually