Board Thread:Theories and Rumors/@comment-30922198-20170119153924/@comment-30499831-20170119221158

Dr. Julien created a human-like robot that was so human-ish, that it could eat, sleep, and according to Tommy, possibly even use the bathroom. It's not that hard to buy compared to tha. It's not like Ninjago is breaking new ground having a robot that can function under water. Like.. Megaman.

If you want an explanation, maybe his skin (human, now titanium) works as a sealant.