Ah yes, like the "smart" decoy flare that was supposed to share some of the launch aircraft's forward velocity (normal flares are ejected sideways, which a half-smart heat-seeking missile could immediately reject as a legitimate target because such a manoeuvre would be impossible for an aircraft), but instead overtook the launch aircraft, no doubt inducing an expensive g-suit trouser accident for the pilot.
There's also the tale of Prof. Kevin Warwick, who announced he was going to run the first half-marathon with a robot companion.
The robot was equipped with heat-sensors and was supposed to track a significant heat-source, like the good professor.
The device had never been tested outside the lab, and, on the morning of the race, the device was switched on in the car park near the start.
It immediately latched onto the best heat source, and set off towards it.
Sadly, it was never going to achieve escape velocity, or manage the 150 million kilometres to the source, and it hit a kerb and wrecked itself on the far side of the car park.