The mongoose indicates the qualities such as smartness, playfulness and fierce to move on. The one who was dreaming about it, is having these qualities of the mongoose. Alternatively, the dream could represent some individual from dreamers life who has the qualities of the mongoose.
Dream dictionary: Mongoose dream meanings
(See Weasel)
…(Marten | Mongoose) In a dream, a weasel represents an insolent person, a fool and a stupid man who is unjust and ruthless. If a weasel enters a house in a dream, it means that evil or adversities may take place inside one’s dwellings. A weasel is the only mammal that can kiss a snake. Thus, seeing a weasel in a dream may represent a prostitute or adultery. Fighting with a weasel in a dream means fighting with a prostitute or an adulteress….