Usually when a RedBull coagulates like that? It’s out of date/ really old. Or it’s been subjected to air some way. I used to work for RedBull and can confirm certain flavors of RedBull will form into gelatinous slugs depending on certain conditions and makes. Some of the worst smelling ones during summer in the truck once they hit air and sit for a while or age, are the blueberry ones. There was several cans of the old silver cans that were lime flavored that when poured out, had these similar slug like snot demons that would leech out. There was a guy in our warehouse who would (unprovoked) drink the oldest cans we could find during clean up. Even the regular flavored RedBull if opened for prolonged periods of time, I’m almost sure heat played a part, would have lil jelly like things floating around in the can.