The Hitchhiker's Guide to the Galaxy Trivia Questions

Answer: Marvin

Marvin uses the gun they retrieve from Deep Thought for Humma Kavula, to defeat the Vogons. The gun makes whomever you shoot with it think the same as you do, so Marvin uses the gun to make all the Vogons depressed and they fall over. After this, Marvin, Zaphod, Trillian, Arthur, Questular Rontok and Slartibartfast leave for the Heart of Gold once again.

Answer: His arm and hand

While visiting Humma Kavula, Trillian is captured by the Vogans and taken back to their home land with them. Arthur, Ford, and Zaphod follow the Vogans to rescue Trillian.

On reaching the heart of Vogsphere, Arthur asks Marvin for a hand and then bursts into the nearest building holding the arm and hand as thought it was a gun, demanding the release of Trillian.

This however doesn't work, as the Vogan at the counter tells them that this isn't the right place for robot repairs.