My son wanted to be a garden gnome. We started looking for ideas and came up with a garden gnome sitting on top of a mushroom!.
We used a plastic snow sled turned up side down as the top of the mushroom. We cut a hole in the center large enough for him to fit into it. We attached rope to the sled by drilling holes and crisscrossed the ropes in the back to hold the mushroom in place. We then hot glued red fabric to the sled. We cut out white felt in various sizes and glued them on top.
The boots were toddler rain boots and we used a pair of black toddler pants filled with a cut pool noodle for the legs. We drilled holed in the back of the boots and zip tied them to the top of the mushroom. He wore an oversized t-shirt to cover the ropes and the top of the mushroom. It also hid the top of the pants. We used a belt to keep everything in place.
The hat was an old Santa hat with pom-pom cut off. We rolled stiff paper into a cone shape to keep the hat upright.
He had so much fun wearing this costume. He was constantly asked if people could take a picture of him.