Kerbal Space Program - The Magic Ladder (to Eve and back)

A kerbal on a ladder has its mass and drag ignored by the parent craft, which is obviously very powerful for mass optimization. This craft can do an Eve return in under 4 tons. Mass without kerbal and without cargo is 3996 kg; mass with cargo but without pilot is 4061 kg.

This is very similar to, but distinct from, the ladder kraken drive. The only force exerted on the lander is from propellers and engines (and air resistance). However the basic principle is similar - a kerbal cannot transfer force to a ladder, so in this mission the kerbal is effectively massless and dragless, while in a kraken drive it can push against another part and create an unbalanced force. This should be legal under the standard low mass rule set, although I wouldn't be surprised if the rules were changed afterward.

Thanks to Ultimate Steve for discovering this and showing me.

Music: Sung - Cosmic Road