Camille, the Void Crawler
I've been thinking of many champion concepts ever since the featured gamemode Black Market Brawlers, but I've forgotten many of them. When I saw this post from SmoovePyro, it reminded me of one. Please check his out. http://boards.na.leagueoflegends.com/en/c/skin-champion-concepts/dEvummAj-fisib-the-void-crawler
I remember this Camille's model being a mix of Rek'Sai and a chameleon. This champion should turn out to become a mid laner with a playstyle of a trickster, but not Fizz.
P : Momentum of the Void Camille can move through units and passively gains movement speed and grants stacks, which discharges onto another enemy champion on auto attack or spell scaling with level depending on how much stacks she has before discharging. She also gains a short burst of bonus movement speed for discharging the stacks.
Q : Whiplash | 12/11/10/9/8 | 50 mana at all ranks Camille lashes her tongue out in a medium ranged skillshot does magic damage and applies a % current health DoT that lasts for 2 seconds.
W : Void Cloak | No cost After channeling for 0.5 seconds, Camille will seem to disappear to all enemy champions (not stealth) and vanish from the map for 6 seconds. She cannot use this ability again until her Whiplash has hit an enemy champion or she has reformed from Imposter.
E : Incursion | 16/15/14/13/12 | 80 mana Camille blinks to an area and upon landing, if there is an enemy champion, she will perform a double strike (70% AP) .
R : Imposter | 110/100/90 | 150 mana After channeling for 0.75 seconds, Camille morphs into the enemy champion, copying their base stats, items, and skill set for 6 seconds. After 6 seconds, Camille will appear from the void once again, providing her a shield for 3 seconds and surging the area with void energy, stunning enemy champions for 1.75 seconds.
Lore : Camille was one of the creatures amongst the Void to be. Allied once as Malzahar's acquaintance, Camille no longer wanted to have a contract with him allying them together. Roaming about for miles under the Shuriman sun, lay a mysterious, surging portal of Void energy. Out of curiosity, Camille entered the portal, unaware of the horrific sights. Upon entering the Void, the Void portal closed. She could not get back to Shurima. After months of exposure to the void, void essence had rushed into her very vessels, changing her personality and her body, creating a monster. A man, who had come to explore 
(kappa) had been in the Void for a few hours and was enduring the visions and horrors of a hell. From a thirst of entertainment and a thirst to view fear, Camille infected the man with pain that made him psychotic. His screams were enough to rupture the barriers between Runeterra and the Void, creating a portal, where the man had his arm dissolved into the essence of the Void in order to leave to Runeterra. Camille remained in the Void.