In my dream i kicked a boy and my leg moved in real life, why?

It happened twice, first i tried to kick a boy in my dream and i kicked the wall (it hurt a little bit) and today i was trying to kill a monster that looked like a mole in my dream and when i woke up my foot was moving. My friend told me it's dangerous because i don't have sleep paralysis and i could be using a knife in my dream and then do it in real life but i don't believe him. What's your opinion?

I reckon it can happen with violent and sudden movements. I know I get sleep paralysis as I've consciously had it quite a few times. Once, however, I was concentrating very hard on hitting a tennis ball with a racket in a dream and it moved my real arm, waking me up.