HA ! ........... spline drive !
i have a brand new, still in the box, set of 1/4" drive [size ratchet] "spline drive" sockets and bits, with the spline drive on all the parts so you can't use the individual pieces with anything but this set.
i don't remember where they came from, if i remember, i think it was a door prize at a cruise.
probably a donation that was a "can't sell" item.