A device, machine, or other construct that will inevitably fail, given enough time, and that will be devastating in the amount of fail it causes when it does.
This 1 TB SSD is worth by far more than the rest of my entire computer, but it's a ticking failbomb.
A person who fails at blowing things up...
That guy who tried to blow up Times Square in NYC; yeah, he's a failbomber.
a phrase used to say that someone is going to fail in the near future
Human 1: Hey, did you hear that the 6th grader Evan is gonna fight that 8th grader Carl?
Human 2: Doesn't Carl have a blackbelt in karate?
Human 1: Yeah.
Human 2: Dude, Evan is gonna drop the failbomb