I need help creating monsters for an adventure.

[raptor112]

There could be a five minute "break" between phases as the first form "phases out" (is removed from play) and while it's taking 5 minutes to transform, the PCs can take a short rest. (It'll be funny if they don't. Really.)

I was toying with not giving a short rest, hence why the first form is a stardard monster. They can gang up on it, kill him in a round or two and then SURPRISE killer steampunk cyborg