These sturdy leather boots appear to have monstrous mouths along their soles.  While wearing these boots, you can use and action to cause them to polymorph their form to resemble any pair of footwear.  You can also speak a command word to cause them to start or stop secreting a powerful adhesive.  While the boots are secreting adhesive, you can only move half your speed, but gain a climb speed equal to your halved speed.  While climbing using the boots' adhesive, you can move up, down, and across vertical surfaces and upside down along ceilings, while leaving your hands free.  Slippery surfaces, such as those covered by ice or oil are considered difficult terrain.  In addition, if an effect would move you against your will along or off of a surface you are standing on, you have advantage on the saving throw against the effect.  On a successful save, you are not moved.

Also while wearing these boots, you can kick a target with them.  A kick with these boots is an unarmed strike that deals an additional 1d4 piercing damage plus 1d4 acid damage.

The boots have a 50% chance of actually being a pair of mimics.  Casting the identify spell on the boots reveals if they are mimics or not.  If the boots are revealed to be mimics, how the mimics react to being discovered is up to the DM.

Boot Mimic

Tiny monstrosity (shapechanger), neutral

Armor Class 12 (Natural Armor)
Hit Points 5 (2d4 + 0)
Speed 15 ft.

Skills Stealth +5

Damage Immunities acid

Condition Immunities prone

Senses darkvision 60 ft., passive Perception 11

Languages Common, Undercommon

Challenge 1/4 (50 XP)

Shapechanger. The mimic can use its action to polymorph into any footwear 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.

Adhesive (Object Form Only). The mimic adheres to anything that touches it. A Medium or smaller creature adhered to the mimic is also grappled by it (escape DC 11). Ability checks made to escape this grapple have disadvantage.

False Appearance (Object Form Only). While the mimic remains motionless, it is indistinguishable from an ordinary boot.

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

Paired Split. Boot mimics are always encountered in pairs.  Whenever one boot mimic in a pair is reduced to 0 hit points, the remaining boot mimic can use its reaction to split into two new boot mimics if it has at least 2 hit points. Each new boot mimic has hit points equal to half the original boot mimic's, rounded up.

Twinned.  Both boot mimics in a pair share an initiative.  When initiative is rolled, both boot mimics roll separately, and use whichever initiative count is higher between the two.

Mimic Boots. A pair of mimics can be worn as footwear.  While acting as footwear for another creature the mimics take no actions of its own.  An attuned wearer can command the mimics to polymorph to resemble any footwear.  The wearer can also command the mimics to secrete Adhesive; doing so halves the wearer's movement speed, but grants them a climbing speed equal to their halved speed.  While granted a climbing speed by the mimics, the creature can move up, down, and across vertical surfaces and upside down along ceilings, while leaving its hands free. Slippery surfaces, such as one covered by ice or oil are considered difficult terrain while climbing. 

If an effect would move the wearer against its will along or off of a surface it is standing on, it has advantage on the saving throw against the effect.  On a successful save, it is not moved.  Additionally, the wearer can use the boots to make a kick melee weapon attack.  A kick attack is an unarmed strike that deals additional damage equal to the mimic's bite damage.

The mimic is immune to game effects that would damage or destroy items with acid such as a black pudding's Pseudopod attack.  Non-acid game effects that would damage or destroy weapons deal 1d4 damage to the mimic instead of lower its damage rolls.  If an attack or game effect would reduce the mimic to 0 hit points while it is being worn and its wearer has at least 1 hit point, the mimic drops to 1 hit point instead.  While the mimic has 1 hit point the wearer loses all benefits provided by the mimic.  The mimic is considered a destroyed item until its hit points rise above 1.

Actions

Pseudopod. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 2 (1d4) bludgeoning damage. If the mimic is in object form, the target is subjected to its Adhesive trait.

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 2 (1d4) piercing damage plus 2 (1d4) acid damage.  If the target is wearing the mimic, it takes double damage.

Description

Boot mimics pose as well made or even magical footwear to make themselves desirable to adventurers. They seek out caches of treasure to hide among valuable objects.  Once picked up by an adventurer, boot mimics will travel with their new owners.  By night, while an owner sleeps, the mimics will rummage through their belongings in search of food.  If discovered (usually when a new owner attempts to identify them) boot mimics will often try to negotiate; offering to serve the adventurer as a magical set of boots in exchange for regular payments of food.

Boot mimics apparently always travel in pairs.  However, there is debate as to whether or not the two boots are actually separate creatures, or the same creature capitalizing on a strange or magical function that allows it to divide its own body and control the parts independently.  What is known is that there is never only one boot in the set.  Even is one of the boots is killed or destroyed, by the next morning, there will once again be a pair.

Notes: Set: Innate Speed (Climbing), Damage: Piercing, Damage: Acid, Damage, Movement, Utility, Combat, Shapechanging, Footwear, Sentient