Hussar
Legend
There are some really excellent points in here.
I think it can be boiled down to, as a DM, actually describe things rather than rely on the crutch of labels. Any encounter becomes more interesting when the players aren't sure of what's going on.
The idea of the vampire cube, the displacer beast and the others are just great ideas. Don't let the mechanical aspects of the game tie you down. Let them allow you to bring your creations to life and still guide you into not obliterating your PC's. In other words, the rules are there to help you, not hinder you. Use the rules. They really do work when you let them.
I think it can be boiled down to, as a DM, actually describe things rather than rely on the crutch of labels. Any encounter becomes more interesting when the players aren't sure of what's going on.
The idea of the vampire cube, the displacer beast and the others are just great ideas. Don't let the mechanical aspects of the game tie you down. Let them allow you to bring your creations to life and still guide you into not obliterating your PC's. In other words, the rules are there to help you, not hinder you. Use the rules. They really do work when you let them.