Which new units did you like in World of Xeen?

I'm reading this thread and realize that I haven't seen more than half of the creatures being discussed:confused:, even though I've encountered all sorts of messengers (of peace, war, etc.: 2000 hit points each, and they don't attack anyone on the battlefield) and griffins (and, I think, on the same map). But what are these nightmares, sorceresses, metamorphs, and Santa Gremlins? Explain it to me, please:smile33:!