I used polymer clay, two little black glass beads, and a ball of tin foil about the size of a small fist.
I shoved the tin foil in the pot and flattened it down so i wouldnt waste clay, and then I covered it with a thin layer of brown clay, for the dirt.
The rest is pretty easy, make a thick cylinder and round off the top, add some glass beads and a mouth. Add some arms that are smaller cylinders bent in half. Take some little spikes with translucent polymer clay wherever you want (you should probably add more than I did)
Attach the cactus to the tinfoil by shoving a toothpick half way into the cactus then poking it down through the tin foil and the "dirt". Remove the tinfoil and cactus from the pot and DO NOT bake the pot, after it is baked and cooled just glue it in so it stays put, and your done(: