Not quite the dumbest but whilst we are on the subject........
Landed a Lynx during a lull in tasking on an exercise and got handed a couple of Ginsters pasties as it was some hours since brekkies. Deciding they would taste better warmed up, I placed them under the engine, through the fire hatch. Co-pilot re-appears to tell me that endex has been called and we are released so off we go forgetting about said pasties. Landed for a refuel at a busy airport in the North West about an hour later and, whilst doing the post flight inspection discovered said pasties steaming away.