HM slave

From HM, an abbreviation of Hidden Machine, adapted from Japanese ひでんマシン (Hiden Mashin, “Secret Machine”).

HM slave (plural HM slaves)

1. (Pokémon video games, fandom slang) A Pokémon retained by the player to use Hidden Machine moves (certain moves that usually help in exploring the world of the games).
   • 2001 February 17, Talen, “Re: [OT] Frustration...”, in alt.fan.dragonball‎ (Usenet), message-ID <qohs8tgvf0jap8p9fto88fufl17blr740f@4ax.com>:

     Farfetch'd is pretty good for a HM slave. And once you've visited everywhere, you can HM delete Cut and Flash and False Swipe and raise it to a decent level and watch it own damn near everything.

   • 2001 February 15, rak...@mindspring.com, “Re: Smeargle just an ugly smear in your team?”, in alt.games.nintendo.pokemon‎ (Usenet), message-ID <3a8b4f6a.316743@news.mindspring.com>:

     That leaves Flash, Waterfall, Fly, and (not a HM, but needed in much the same way) Rock Smash for another HM slave.

   • 2005 May 17, daramark, “Re: New player strategy.”, in alt.games.nintendo.pokemon‎ (Usenet), message-ID <Pkeie.1739$dS3.443546@news20.bellglobal.com>:

     I think the HM slaves work best because then you just have to level them up to about 40 playing through the game, and switching them out for some other more useful pokes leveling up.

   • 2015, Pokémon X & Y - Strategy Guide, GamerGuides.com, →ISBN, page 24:

     For this purpose, some players like to bring along a "HM Slave" (or two) - a Pokémon whose only purpose is to use HMs.