"Boogeyman"
I got this idea from watching "Constantine" with Keanu Reeves and "The Nightmare Before Christmas". This is based on the bug-man creature and the boogeyman.
Melee champ with no mana. All attacks take a little bit of your health.
Passive: Parasite - Every spell you land your bugs latch onto the target. This grants you vision of them. If target dies with a critter on them you gain a Critter Minion that attacks the nearest champion. Able to be applied on minions/champions. Each spell cast takes a little of your health.
Q: Swarm - Send a swarm out to a target in a straight path, all enemies hit gain a Parasite. Decreased damage to subsequent targets.
W: Call of the Cicada - Calls back all your Parasites (passive). You gain x health based on the bugs that return.
E: Insect Sphere - Send a swarm that slows a target and slowly eat away at your opponent (DOT)
R: Locust Swarm - Swarms of insects swarm to you and enemy champions that has a stack of your bugs. Enemies get a insect sphere that slows AND blinds them. You also gain a temporary shield due to the heavy amount of insects around you.