Well, I'm sure you could create something neat. If you wanted to do the building (or partial building), the balsa wood and mitre saw should help you out. I'd guess the saw and box are around $15. Typical ones are setup for cuts at 90 degrees and 45 degrees. Though I've seen some that offer more options. If you don't already have a selection of balsa wood, they've got bags with a variety of sizes for $5-10 I believe.
If you want to mimic destruction, the balsa wood is great too. You can build a door (cut the pieces to size, glue it together, let it dry) and then break it apart. The wood will break and smash, then you can glue the pieces on the ground in front of your monster. Before you break it up, be sure to have a go at it with your hobby knife. The balsa is a bit too uniform. So round off those edges, add some chips and scrapes. Again, take a look at the bare version I did on the Saxon. You can see how the main post is all cut up to make it look more realistic. And, while I didn't smash up a door, I did build a chair and then broke it apart for the Saxon base. I think you could do something neat with this guy, though you may come up with an even better idea than mine. Keep me posted, I'm happy to offer advice on construction if you decide to go that way.
By the way, the story nature to the pieces is a big deal in diorama (of course) and large scale. But it can help entries in any category stand out. I'm not sure a lot of people really take advantage of that in the monster category, so it could help yours shine!