In a forum thread about difficult-to-run monsters, some people expressed difficulty with beholders. However, it occurs to me that, aside from the superficial differences in appearance, they make good daleks. Or the Martians from War of the Worlds.
I mean, they hover and they shoot rays out of their eyes and they hate other creatures. I think turning them into secret masterminds is almost a mistake. They're called "eye tyrants", so they should TYRANNIZE!