The witches contain some sort of audio sensor so they cackle in a manic fashion and wave their arms about if you clap your hands in front of them. No, I didn't buy one - but I know someone who did.
I've got both, my own personal witch bought one of the Symi ones last year it hangs just inside the back door so it is the first thing I see when I come home I think it is so she looks good in comparison when she greets me ouch ouch ouch !!!sorry dear