I’ve been stung by many api (bees) and vespe (wasps) in my lifetime, but I thank my lucky stars that I’ve never been on the receiving end of a calabrone sting!
The word calabrone comes from the Latin crabronem of the same meaning.

Calabrone is a masculine noun. The plural is calabroni.
un calabrone
il calabrone
dei calabroni
i calabroni
A hornet sting is una puntura di calabrone and the phrase to be stung by a hornet translates as essere punto/a da un calabrone. The part that holds the sting is called pungiglione (stinger).
Cosa accade quando si viene punti da un calabrone? – La puntura può provocare uno shock anafilattico nelle persone che sono allergiche al veleno iniettato dall’insetto.
What happens when you get stung by a hornet? – The sting can cause anaphylactic shock in people who are allergic to the venom injected by the insect.

The idiomatic expression essere nero come un calabrone (to be as black as a hornet) describes someone with a very brown complexion, since hornets are dark in colour. In a figurative sense, it denotes a person who is in a very bad mood.
Since hornets, in addition to being dangerous, can also be quite irritating, the word also has the figurative meaning of pest or nuisance.