https://en.wikipedia.org/wiki/List_of_instruments_by_Harry_Partch#Bass_Marimba_and_Marimba_Eroica

Archived request from the wiki:

Bass Marimba

• Family: Percussion
• Description:
• Appears on:
  1. Kärlek & politik
  2. Wall-E
  3. Unerreichbar
  4. Our Pleasure to Serve You (track 4, played by George Devens)
• Comments:
  • Not very common. The author of http://www.craftymusicteachers.com/bassmarimba/ has heard from percussion supply dealers that there are few bass marimbas around, mainly at music schools