YiffieMon:Critical Failure

The Creature failed as completely as it is possible to fail. Anything that can go wrong goes wrong. If attempting to repair a device, the device is further damaged or even destroyed. In a social situation, the Creature gets into further trouble.

Not only do you not achieve the desired result at all, but you suffer a complication like in But Success.

You automatically fail all subsequent attempts at doing the same task after a Critical Failure until you get a day's rest.