Skittles is what I call my multi-color plasma shots. These made their first appearance in my Mining Praxis level/map.

colorful plasma colorful cellpack colorful cell

And you can have them too! Available for download, skittles includes the graphics as well as the DECORATE code to swap in multi-color plasma shots into any game of Doom you wish. (ZDoom-based ports only) Also included in the wad file are the custom animated cell and cell-pack ammo sprites and their accompanying DECORATE code.