Hornets

Hornets are the largest of the social wasps.  Flying hornets which are hunting and which are not close to their nest will usually not sting, unless they feel threatened.  They should not be squeezed; making a breeze at them can also irritate them and make them feel threatened.

Hornets can alert the whole nest.  This means that all workers there will defend it.  This can lead to a dangerous situation.  One sting of a hornet is not dangerous; with 200 to 250 of them, the situation is different.

https://simple.wikipedia.org/wiki/Hornet