Ideas to stop them.
1. Get two Pumpkins. One for real, one is covered in Greece. Put the Greecey one on the Porch, and Let them try to Pick it up, and get the Revenge,
2. Get some eggs, wait for them to try to take the Pumpkin, and throw the eggs at them.
3. Get an Air Rifle, wait for them to try to take the Pumpkin, and scare them into thinking you're going to shoot them.
4. Dress like an Old Lady, wait for them to try to take the Pumpkin, and then run out at them, and beat them with a Cane
5. Just put it on your roof so they can't reach it.