Apologies if this was intended or is already know, but I've found out that Endermen cannot attack the player while riding a Golurk (as seen in the screenshot below). This can be exploited to grind Minecraft or even RPG experience on certain servers, such as Oblique. It's a minor thing I've noticed, but I thought it'd be worth mentioning.
https://puu.sh/w9k1b/06ee9a46d0.png