Literal translation: Like a fly without a head.
Meaning: Flies are not exactly considered to be the rocket scientists of the animal kingdom. The phrase ‘’running around like a fly without a head’’ is meant to describe someone going about something in a stupid frenzy without a plan or an exact idea about what they are trying to achieve. Kind of like a fly buzzing aimlessly and crashing into something every two seconds.
Use: Someone crossing the busy intersection on a red light, escaping getting hit by a car by inches, causing breaking, honking and road rage.