Necrons: Canoptek Spyder

Unlike their Necron masters, Canoptek Spyders never sleep, but while away the aeons servicing the structures of their Tomb World. Though the Canoptek Spyder is essentially an automated drone, it is still a formidable foe when the situation demands. Any enemy foolish enough to stray within reach of the Canoptek Spyder will have flesh scoured from bone by an array of mechanical tools and pincers. If a triad of Canoptek Spyders operate together, one takes overall command, harnessing the processing capacity of the others to create a supermind far greater than the sum of its parts. This hyper-efficiency is passed on to all Canoptek Wraiths and Canoptek Scarabs in the immediate vicinity, allowing a co-ordinated and precise response to any threat - and ensuring the safety of their slumbering masters.

When it comes to ferocious mechanical constructs, you can't get much nastier than a Canoptek Spyder. If it isn't tearing apart enemy infantry or tanks with an array of hooks and blades, then it can be used to repair your damaged vehicles. The icing on the cake (or the chip on the circuit board - whatever the Necron equivalent of cake is) is that, even in the heat of battle, it can spawn Canoptek Scarabs to boost your war efforts and irritate your foes.