Give any champion another champion's passive

Just like the title says. What champion would be amazing if they had someone else's passive?

Obvioiusly some champions don't function without their own passive (Illaoi, for example), and others won't translate well (Syndra's passive would be meaningless to someone with different abilities), but we should be able to get some good ones nonetheless.

I'll start:

Heimerdinger with Morgana's passive (20% spell vamp, which turrets would proc). Karthus with Annie's passive (his Q's cooldown is crazy short, and a global stun on his ult at the cost of his post-death party). Teemo with Master Yi's passive (too much poison)