we called em suicides!
My buddy used to do that every time we went to 7-11. He'd take a Big Gulp cup over to the self-serve soda fountain and squirt a little bit of each soda (Pepsi, Mountain Dew, Root Beer, Orange, etc.) into it till it was full. It always looked nasty as hell and I'd say "Dude, that is just not right." Never heard'em called "Suicides" tho.
We called 'em graveyards at the theater!