The Weasel is the secondary antagonist of Men in Black 3.
Personality[]
The Weasel is extremely loyal to Boris, who uses gutaral vocal commands to control him. The Weasel is very aggressive as well, killing anyone it perceives as a threat to its master.
Role in the film[]
Even though Boris was imprisoned in LunarMax, the Weasel evaded capture for the next 40 years. At the beginning of the film, Boris's girlfriend Lilly comes to LunarMax to visit him, bringing a cake to him. The Weasel turned out to be hiding in the cake, and killed the guards before releasing Boris.
Boris and the Weasel proceeded to track down K at a Chinese restaurant; after failing to kill him there, they resolve to go back in time and team up with their past selves to kill K back then.
At the end of the film, when K freezes and shoots off 1969 Boris's left arm, the Weasel living in his left hand was most likely killed, while the other one, living in 1969 Boris's right hand, survived. When K kills Boris. the Weasel dies along with him.