A Quark for Muster Mark!

Enchant land that produces blue, red, or green
mana.

When enchanted land is tapped for blue, red,
or green mana, it also produces antiblue, antired, or antigreen mana respectively. (An anticoloured mana annihilates its respective coloured mana in the same mana pool, e.g. a mana pool with 2 blue and 1 antiblue mana is a mana pool with only 1 blue mana).