Not a bike item, but the basin wrench. The chunky forged item with cranked jaws just oversized enough to round off the back nuts on taps, and with shoulders so big and jaws so long that you can maybe turn the nut 5 degrees before it hits something under the sink/bath.
@TLP, tried a Windjammer neoprene draught excluder - only just got it on, nearly ripped my ears off getting it back off. Wearing a flip lid now, binned the item.
@MartinW, my mental picture of the tyre inflator has just acquired another level of silliness - trying to use it on a single cyliner kickstart only bike.