i posted a bug about ashe's ult going through characters who were in the middle of a movement based ability previously.
i would like to add to that, specifically about cho'gath, and im assuming nasus, though i haven't confirmed it with the latter.
they both have abilities which make the grow physically larger on screen. however, and i dont know what you call this exactly, but the space that the computer thinks that they take up stays very small. so when cho has fed 6 times, he takes up damn near half a lane by himself, but i've seen an arrow go through him 1/3 of the way into his body and not hit.