So I was in first place in Mario Kart DX while racing online (because of course I was in first) when a Koopa Kid comes flying out of nowhere and zooms past me. It seemed kinda strange to me so I went back to the replay and sure enough the character literally just appears out of thin air with a mushroom.

So this made no sense to me so I switched the camera angle to follow the Koopa Kid and from that perspective the character also just teleports to a new location.

What the hell? Haunted player? Hacks? Ghosts? Glitchy network? It is one thing to get knocked out of first because of a blue shell but these kinds of shenanigans are something else entirely. Do any of you have any explanation for this?

As far as I understand it, the replay saves whatever your game client thought was going on. I've seen replays where my game thought a guy was driving against a wall for 5 seconds, but actually he had just taken the corner normally and the game eventually teleported to where he was supposed to be.

There definitely are people that hack, but the thing you're talking about sounds more like the game's dodgy net code that sometimes loses track of people for a few seconds if one of you has a bad connection or a lot of latency and it mispredicts where they should be.