This afternoon, my manager bought some umbrellas for our office, saying: 'These umbrellas are boomerangs'. I was puzzled as I only knew this word as a weapon originated in Australia, or in the noun phrase 'boomerang effect', or likewise in the verb phrase 'to boomerang against'. So, my manager explained that he meant that we should always return those umbrellas to the office after using them. Have you, as a native speaker, ever heard of this usage?
It's not a common usage, but one of the marvellous things about language is that it is extensible and flexible. This kind of creative use of language is frequently found in poetry. If poets didn't do this, we would find their use of metaphor tired and hackneyed.
When Robert Burns wrote "My love is like a red red rose", he didn't mean it as an analogy. Love isn't red, scented, with thorny stems. He meant it as a metaphor: that the effect of love on him was similar to the effect of looking at a beautiful rose (or something like that).
Saying that the office umbrellas are boomerangs is a poor analogy, but it's OK as a metaphor - we know what he means.
Analogies should have several features that can be mapped from the analogy to the thing being described (e.g. an explanation of an atom containing a nucleus with electrons orbiting round it as being a bit like planets orbiting around the sun - though actually this isn't really how electrons behave).
A metaphor can have only a vague resemblance to the thing being described.
As to whether a boomerang is a good metaphor for an umbrella that must be returned to the office: it may not be great poetry, but it's at least memorable.