One of two main manipulators. These are mounted on powerful arms, and can be used either to transport large pieces of equipment or to shred enemies to pieces (...if only the Beholder can catch anything... ^^)
Heavy plasma cannon. Can attack in any direction, due to mounting on an arm with two ball joints. It is the only energetical weapon of the droid, but it is more effective than whole X-Wing's weapon system together.
Brilliant! Haha, best MOC I've seen on here in quite some time. And it really does look like a robot version of a Beholder (the D&D kind I mean). Great idea, excellent execution. And boy does it look impressive. I wouldn't like to meet that thing on the battlefield!