Why is someone pretty much superhuman or maybe even not human when they black out from anger?

I've blacked out from anger in the past and i genuinely never remembered what I did until i was getting yelled at for it. Apparently ive slapped people. I shoved someone down and repeatedly kicked them in the ribs even though they were asking me to stop but i wouldn't stop and had to be pulled away. I've thrown things. I charged at someone with a shovel and ended up knocking them down and swung the shovel over the top of their back.

All things i never remembered doing but apparently did. I wish i could remember and im always horrified of myself if it happens.