The Irresponsible Cpt. Tylor question

Recently, I started watching the anime The Irresponsible Cpt. Tylor, and it’s great. Incredibly funny, a good storyline, and a great plot. I have one question though…

What’s up with the beaver on the bridge? There’s a point where everything gets serious, and then they do a pan across the bridge at this incredible tense moment, and just sitting there by the door is this four foot beaver looking animal with a old war helmet on. There’s no explaination for it as far as I can tell, is this supposed to be some sort of symbolic thing, or is it just some random act of sillyness the artists put in (like the guy named Jason who wears a hokey mask, doesn’t speak, and carries around a chainsaw)?