A Klingon insect half the size of an Earth mosquito, with no sting but an irritating buzz, used aboard the Enterprise-D as a comparison for a harmless nuisance.
The glob fly is an insect of the Klingon homeworld. It is about half the size of a terrestrial mosquito and cannot sting, but makes a loud and maddening buzz.
It is mentioned in The Outrageous Okona. When a small and feebly armed vessel locks its weapons on the Enterprise-D and demands the surrender of the roguish freighter captain Thadiun Okona, the bridge officers are more amused than alarmed. The threat is compared to that of a Klingon glob fly, and Worf supplies the particulars of the creature for those unfamiliar with it.
The comparison holds: the ships of the two feuding planets can do the Enterprise no harm, and the real difficulty is untangling the family quarrel behind their demands.