Well, if you're okay with slaughtering an entire town, we could totally make ourselves a bloodfire ooze. They're pretty nasty, especially if we get some fire-casters (free Empower? Yes please!) Mostly it requires the blood of a thousand humanoids or something. Oh, and a 6-HD Outsider, but we'll burn that bridge down when we get to it. We could even keep it in the acid pit (instead of acid), so that people get lowered into blood that is of searing heat, while it tries to eat them.