[Sion ultimate skin] Fusion
Imagine a Sion ultimate skin called Fusion. His stomach would have a giant radioactive warning symbol. His open mouth would be dripping and glowing with green radioactive material. A glowing green plutonium rod would be stuck into his skull. His gloves would be yellow hazmat-style forearm-length like you would imagine a mad scientist would wear. His boots would be huge with bolts through the ankles evoking thoughts of Frankenstein's monster. His weapon would be a huge hammer with green electric crackles.
His abilities would all incorporate leaking radioactive material and nuclear explosions/reactions:
Passive: his gloves are blown off revealing leaking green glowing sludge-covered fists hat constantly drip to the ground
Q: instead of just an icon filling up, the ground slowly gets covered in the AOE with a glowing green puddle. When his weapon is slammed down, there is a mushroom cloud explosion that knocks enemies up into the air.
W: a cloud of excited glowing green particles flies around him like a horrible radioactive force field. When it detonates, well, it's green and glowing instead of red. Boom.
E: a glob of dripping radioactive goo is spit from his mouth instead of the current whatever-that-is. Minions and monsters shoved by it glow green and spark with radioactive particles as they fly through the air
R: an air raid siren plays instead of the current "dong" sound. The effect around sion looks more like he is a missile being propelled by some ungodly nuclear reaction. When he hits/completes the ult, there is an awesome mushroom cloud nuclear explosion.
It's just an idea I had. A freaking cool idea.