Replying to Claimasauras

Well, I feel bad for creating two site discussion threads in one day, but I felt both questions would be good for people to see the answers to.

Since there is nothing in the searchbar about it, I figured I might as well make a thread.

Question: What does the claimasauras have strapped to its back? I know it's probably just meant to be random, but if I'm wearing the shirt and people ask me what it's about, I'd like to be able to answer with something better than "it's random, I dunno".

Please and thank you.