Minecraft 1.7.10
MCP v9.05
FML v7.10.99.99
Minecraft Forge 10.13.4.1492
Optifine OptiFine_1.7.10_HD_C1
Mekanism-1.7.10-8.1.7.252
MekanismGenerators-1.7.10-8.1.7.252
MekanismTools-1.7.10-8.1.7.252

Pretty self explanatory. The Golden Lasso from Extra Utilities (which is designed to contain entities), when used on Robit, will crash the game. My guess is that Mekanism is calling for Robit's interface when right clicked, but at the same time, the Golden Lasso is trying to contain Robit. Seems like a crash-causing paradox. Though when I reloaded the game, Robit was contained in the Golden Lasso.

https://drive.google.com/file/d/0B_wljXPJi507TEpRU2lNa1piTG8/view?usp=sharing