A Cybran ACU from the orignal Supreme Commander.
I mean, seriously, it constantly generates matter and energy, builds buildings that generate matter and energy, is undetectable by anything other than an omni-radar array, can teleport outside the blast radious of a nuke, builds some of the most stupidly overpowered units ever, builds buildings that build units that build said stupidly OP units and has a laser on its arm that belongs to one of the afformaentioned OP units.
Oh, and if you give it about a day, it will build enough nukes to shame North Korea. Now why would I want anyting else?