>>535971339
I honestly think it might be this ominous thing from the original Air Ride. You know, the shadowy blinking mass you don't notice in the actual race but jumpscares you with a tactical camera shot in recaps.
Speculation: Machine Passage seems like the Orange Ocean base the Meta-Knights launched the Halberd from back in Super Star. Didn't the Halberd have some strange unexplained test tube creatures in Smash Brawl? Seems a lot like a lost plot point from Kirby GCN, which was likely going to have the same Halberd design. In fact, I'm 80% sure Kirby GCN was going to be Sakurai and Shimomura's Super Star sequel. Yes, the lost Kirby game just won't go away.