so like, what is the holy spirit?

the father i get, thats god. the son i get, thats jesus. but where does the holy spirit come from??? i asked a bunch of my christian friends in high school and the only good explanation i got was that it’s jesus’ ghost, and that the reason it still exists after he revived is bc he exists outside of time?? so he’s a time-traveling jesus force-ghost?? which doesn’t really make sense to me bc it seems kinda sci-fi-y. so like. what is the holy spirit?