Replying to Werid Sleep Thing

Idk if its just me or this actually happens to other people. Sometimes when i just fall asleep, i get like a jolt of energy through my body that wakes me up really fast. When it wakes me up its like going from complete sleep to fully awake with eyes wide open and everything. The feeling kind of reminds me of getting punched in the face but through the whole body. It doesnt hurt though. Its just really weird like i have no idea what it could possibly be. Does anyone else have this happen to them or have any info on what the hell it is?