those mf can eat a whole bronto in less than 5 seconds, so if you kill anything big and want to harvest its body, make sure to kill them instantly because they spawned near dead bodies or say bye to the body.
When I saw them for the first time I was like well they are probably not dangerous they are just giant firefly and then they attack me and I won but srsly they are so dangerous so now I am keeping them away from me
Use a torch. They have very little health but are difficult to target. Using fire lights them up and kills them quickly and safely.
Bonus points if they are attacking at night, as you will have several extra, flying torches for a few seconds!