This is a quick and easy "costume" I made in various sizes over the years. It is great for last minute costumes, humorous inexpensive costumes that you can quickly use or remove and store in your car, desk, locker or whatever to resume your usual daily appearance. I made my first incarnation of this when my work decided to have a costume contest and only one lady wore a costume. I went to the cafeteria and purchased the small box of cereal, used a plastic knife some red ink and a string for the neck hanger and wore it to support her effort. It was well received and got the desired laughs. I have since made others and this is the latest version from last Halloween. I decided that since I was a cereal killer I should take a Life, thus the cereal choice. You may choose to use Count Chocula or some other cereal that is your favorite. After all you should like it if you are going to kill off a whole box of it. The prop knife is something readily available this time of year. I went to a craft store and bought a bottle or red puffy paint to give the fake blood more body. The neck strap was a shoulder strap from an old laptop bag. So as you can see, very inexpensive to make. I know there are a ton of really great costumes on here and the skill level for this is low but perhaps the idea will bail someone out when they need a last minute costume. Once you have your materials it takes less than a half hour to assemble (plus drying time for the red paint or ink you choose to use). Rather than list steps like "remove cereal bag from box" I've only got a couple suggestions.
Sorry the pictures aren't better and the steps presented a little more formally but I put this up on a whim. I hope someone enjoys it and can use it.
Step 1: Anchor the Knife
I used duct tape inside the box to hold the knife in position but you
can choose whatever you feel works best to hold it in place. You don't want it to move, fall out or the inevitable clown that tries to pull it out or it will mess up the paint ink or whatever you use from not matching up to the box and knife.
If needed you can place a weight in the bottom of the box to help it hang better but I've never needed one and if you do don't go heavy.
Step 2: Watch the Balance
Place the "knife" low on the box so it's weight doesn't pull the box away from your body.
Put the strap holes or slots toward the front of the box to again help it stay against the body.