The Snake-Rider
This is a silly idea.
Remember the video game: Snake? You controlled a line that was always moving. You had to go around consuming dots and with every dot consumed, the line got bigger. If you ran the line into a wall or into itself, the game was over.
What if there was champion that rides a giant snake? We will call the snake-rider Sid. His pet snake is named Spot.
Spot always moves if Sid is mounted. You control the direction with your mouse. Spot has no unit collision so that he can move through units. Spot will be able to consume a minion/monster every so often by running over it. Consuming makes Spot longer. If Spot is lead into a wall, or into himself, Sid is knocked off taking damage. Sid can hop thin walls with this knock off.
Sid's ultimate would be to mount or dismount Spot. Mounting would require Sid being within melee range of Spot's head. Dismounting will have a cast time. No ditching Spot after realizing you cannot turn fast enough to dodge a wall. Sid has two sets of QWE abilities based on whether he is on Spot or not.
I just came up with this idea, so it is not a full concept, but I wanted to see what you guys think of it before I actually put some thought into it. I think it would be fun to see a jungler like this.