Animated Player Effects

I’ve always wondered, how do people make it so you can have like auras and shit, I actually have no idea how this is possible so any links to anything useful would be appreciated.

Do you mean this?

That’s actually something useful which I didn’t know about and i’ll be using it but no, I mean like floating animated things around the player, for example animated glowing things floating around a player’s head. There was another thing that placed some sort of texture (image) below player’s feet and it kept changing size constantly and stuff like that really.