Discord: “Do you know how boring they are? Why don’t you get your crew and help me overthrow th–”
*Discord was interrupted by a hoof to his face*
Luffy: “Don’t talk like you know my crew!”
*Luffy yelled with a volume that made Celestia’s jaw drop*

One of my favourite moments from My Little Pirates: Luffy's Adventures in Equestria fanfic, when Luffy goes against The Lord of Chaos, Discord himself.
I really liked how Discord put more fight than he did in against ponies.

Link: http://www.fimfiction.net/story/192.....s-in-equestria