TMTRAINER#721

TMTRAINER is an unlockable passive item added in The Binding of Isaac: Repentance.

• The name and description of the item comes from the result of glitches in Pokémon Red and Blue. Certain glitch moves in that game can have names so long they run into the memory, corrupting it and causing glitchy effects, like the opponent's name becoming "TMTRAINER". A certain other glitch (commonly referred to as the ZZAZZ glitch) replaces the letters in the player's name with capital Zs except for every third letter.
• The pickup quote for this item is defined as "Isaac and his mother lived alone in a small house on a hill", but in game it's shown with the pattern of Zs overlaid on top.
• When viewed in the collection grid, the pickup quote is unobscured, but it's so long it goes off of the screen.
• The music fading out and status effects being applied to enemies upon acquiring the item is another direct reference to the effects of TMTRAINER in Pokémon Red and Blue, which fades the music out upon use until another song is triggered to play (assuming the game survives the effects), as well as applying burn and frozen statuses to enemy Pokémon.
• The sprite for TMTRAINER itself is a heavily glitched version of the in-game Isaac's Head's face, affected similarly to the face of Tainted Eden in menus.
• For the TMTRAINER sprite in particular is a reference to how sprites corrupt in Pokémon Red and Blue, especially after encountering glitch Pokémon, by segmenting into strips, then rearranged, usually flipped around.
• The effect of the item is similar to a "Randomizer" for other games.
• The item's effect is a reference to an old randomizer mod that came out before Afterbirth+.[1]
• This item is used in DELETE THIS (challenge #45).
• DELETE THIS will always be unlocked before TMTRAINER on any given file. This item, The Small Rock, Dirty Mind, and Spirit Sword are the only items that appear in challenges before they are unlocked. Small Rock and TMTRAINER are also notable for not being unlocked by beating the challenge they appear in.
• MEAT!, YO LISTEN!, G FUEL!, PHD, BBF, BFFS! and TMTRAINER are the only ALL CAPS items in the game.
• Most glitched item sprites are shown as Mega Blast in Isaac's last will. Very rarely one will show a glitchy icon.
• Sounds when picking up glitched items are often changed.