Juicer. It was so large and required so much cleaning. i used it half a dozen times - and never again.
Much the same applies to a soup maker, bought because a friend waxed lyrical about it. I didn't take account of the fact that she is a neat precise, follow the recipe carefully, kind of gal, while I am a hurl it all in the pot and hope for the best person, so between vegetables not cut small enough and putting too much fluid in.
When the element blew within three weeks of buying it - at the start of lockdown and i couldn't get back to the shop to throw it out. I just recycled it. It had been a sale bargain, so not much money had been wasted.
Spiraliser was more effective at spiralising my fingers than the vegetables and the ice cream maker, again, was just too fiddly.