i used to do this as a kid. plop one of these en.wikipedia.org/wiki/Effervescent_tablet (but with fruit flavoring and sugar) in a glass of water, let it fizz a bit, then pour a bit of milk on top. the milk would instantly curdle and stay on top in a layer. it tasted bad. curdled milk with sugar and artificial lemon flavoring. i usually just poured it out after confirming that it still tastes bad.

i have no idea why i did this, it just looked fun.