So let me get this straight: this Mimic-27 is a shapeshifting symbiotic super soldier thing? Basically an organic Doomsday Device. 
History
A specially crafted WMD of Wakandan design, created by the Dora Milaje using notes from Obinna Nwabueze's scientific thesis.[1] Its primary component was discovered in certain cavernous areas near the Adored Ones' training grounds, in discovering the new Vibranium it is made of they came to realize it had replicative imprinting capabilities that would make it useful as a facility in the Dora's arsenal.[2]
The Prof. and the Panther King's wives in training harvested all 27 lbs of the substance that would later comprise the Mimic and set out to harness it using sonic waves from drums outfitted with Treated Vibranium to better tithe & bind the seemingly sentient variant. But the device quickly proved too volatile and unpredictable.
It was instead decided to be kept away from prying eyes whom would be tempted to abuse the potential super battlement. Adored Ones handing it down as a hidden secret passed from sect member to sect member for a generation, until it was discovered and eventually stolen by Advanced Idea Mechanics. Seeking to understand and replicate the potential mega weapon but such plans were cut short when the facility carrying it capsized and sank off the coast of the New York Bay.[3] Sensing opportunity, a former one of their number; the rogue Dora Nakia would seek out the Mimic before her hated sisterhood could acquire it.
Opting to use it in one amongst many inane scheme to attain the eye of her light's attentions before she died. But eventually, Malice lost control of it when Okoye broke the war drum used to guide and direct it.[4] The mimic would rampage all across New York until a contingent of X-Men and Avengers staved it off until the Milaje could put a stop to it.
Properties[]
The Mimic-27 was comprised of a strange Vibranium derivative found at the Echo Chamber hidden within Dora training sanctions. Having realized what it is and everything that it can do, the kingdom's top physicist went to work with the personal guard of the king to harness its emulative practices in order to arsenalize it for the protectorate's use. Unfortunately, its persona-copying aspect made the device unpredictably dangerous to use.[3]
The Mimic's main faculty was its amorphous composition. Enabling it to take whatever shape & form both the utensil user and the item itself wishes too.[1]
At its fullest gauge it possesses the ability to replicate the appearance, mindset and power template of anything or anyone it is faced with. Giving this weapon the power to imitate everything about the adversary it is faced against at a glance.[2] The Mimic can also accommodate bio-fission to utilize multiple ability traits and paraphernalia from the various individuals it comes across. Growing ever stronger over a decent amount of time; becoming a personal army of metapowered projections.
The material comprising it is also highly self expressive, possessing a consciousness all its own.[5] Using that self-awareness to better express the true powers and properties of Vibranium; from causing seismic events, to generating illusions, controlling fauna, and manipulating other forms of Vibranium.[6]