how about a rock paper scissors kind of fusion rifle of elements. it's all 3 elements and has 3 in the mag. each time you shoot is a random element but the first shot has a 1/3 chance to be anything, the second shot has a 1/2 chance to be one of the other two and the final shot will always be the last one. or maybe even make it like the chaos enchantment in skyrim where the shot has a small chance to be 1, or 2, or 3 elements at the same time.