Oh my goodness this plant is going to eat me isn't it?

Hi - me again.
Having had some success with cucumbers, peppers and toms in the past, I decided to try something new and (just for fun) ended up buying a pumpkin plant. At the time it was only a little bigger than my hand and it was coming on lovely. I put it in a medium-sized pot with the intention of researching what on earth I'm supposed to do with it.

Of course...life gets busy and by the time I got around to doing anything - BOOM! It's massive. It has completely taken over the wigwam it's planted inside and appears to be trying to scramble up the side of my shed.

Have I, in fact, purchased a triffid?
I bought a much larger pot designed for veg...will that be okay? Should it be in the ground?

 

They can be a little triffid-esque, do you know what variety it is that you bought?

Steve...