I don't have a fully fleshed out champion, but I have a cool idea for an ability

I'm sure Riot's toyed around with this concept at some point because it's super cool but basically, something that makes you reflect projectiles.

The way I could see it working is for .5 seconds after casting it, any enemy projectile that hits you is reflected back, dealing 50% of the damage it would've dealt to you to the enemy. The other 50% would heal the champion using it. Both of these numbers calculated after armor, so you're really going to end up doing less than 50% damage back since it gets resisted twice. You also still take damage normally from non-projectiles. I'd just like to see something like this show up in the game somehow, I don't really know what other kinds of abilities you'd wanna see on a kit like this but I feel like it's pretty assassin-y.