[Vocabulary] An adjective for 'result'

[Mehrgan]

Hi,

Is there any adjective referring to a situation when an action has backfired/rebounded?

A 'reverse result'? (I don't mean to use 'unanticipated', as it doesn't suggest the negative impact.)

 

[GoesStation]

That's an unintended consequence. Your actions boomeranged. Sorry I can't think of an adjective!

 

[tedmc]

Undesirable/unexpected/untoward/negative