Cheerio, Mate!
I had a friend in sixth grade who went as a cereal killer for Halloween! He stuck pieces of cereal all over his clothes with super-glue, wore about five huge Cheerios necklaces, one over the other, and held a toy butcher knife (with fake blood on it) in his hand!
The highlight of his day was explaining his costume over and over and over again to anyone who didn’t get it. And no – nobody got it. At least not until he explained. I was afraid that this would annoy him, but it made him even more excited. He loved explaining and didn’t stop cracking up for a second. He was really proud of that DIY costume – LOL!