DELETE THIS

DELETE THIS is challenge #45. The goal is to defeat ???. This challenge is unlocked by unlocking Tainted Eden. During this challenge, all items are randomly generated by randomly combining effects from other items in the game. Item sprites and text are randomly generated as well, providing no information on what each item does.

In addition to gameplay changes, the theme of each area, its obstacles per area, and music are randomized. Some obstacle sprites are randomized even with a level and sometimes the music may be missing altogether. Occasionally, even the floor texture might glitch out, replacing it with a plain color.

Strategy

Try to get an active item that has a low charge or does something beneficial. Be warned, as items are randomly generated, active items could also just damage the player.
Item prices in shops can vary significantly, from as low as a single cent to as high as 99 cents.
Trinkets, Cards and Runes are unaffected by the randomization that TMTRAINER forces on other types of items; finding good trinkets such as Curved Horn or Cancer, as well as saving powerful cards such as XIX - The Sun for bad situations, can help give advantages despite your lower-than-usual stats.
Due to the inherent random nature of items, direct stat ups are very rare. As such, Bombs and XIII - Death gain increased utility during this challenge, as their relatively high damage is unaffected by randomization.
Once you have a reliable strategy, stop taking items, as some of their effects (replicating Damocles or mass spawning enemies) can end the run.
Try to finish the challenge as fast as possible, as a game crash is always randomly likely to happen from picking up just one item.

Notes

It is possible for the challenge to be completed early if an item happens to spawn the ending trophy.
Due to the random nature of generated items, it is possible to find an item that makes completing the challenge trivial. Such as an active item with no charges, and deals damage to the whole room which can be spammed to clear each room. Or an item that grants a black heart whenever damage is taken which makes Isaac functionally invincible and causing mass damage whenever touched.
Unlike all other challenges, DELETE THIS appears below the challenge list itself, as an additional challenge not numbered on the list. (The blank space where the invisible challenge " is "; below the challenge list still does get crossed out [like every proper challenge name in the game] after the challenge is complete, however)
All glitched items will appear as the icon for Mega Blast in the pause menu and death screen, though will keep their original glitched appearance on the Extra HUD.
You do not need to pick up the item that spawns after the Mom fight: Isaac will always be transported to the Chest after touching the golden chest that spawns in the Cathedral even if it doesn't seem like he has The Polaroid on him. This does not necessarily apply to golden chests randomly generated by items effects.
Some hardcoded items, like The Small Rock, Steam Sale, or Plum Flute might still appear normally.

Unlockable achievements

Temperance - Complete DELETE THIS (challenge #45).

Trivia

This challenge does not have a name in the game's files at all, and is not merely hidden from the menu: it is defined by the number 45 as its ID and a zero-length character string for a name. For clarity, it is referred to by the name of the achievement that unlocks it.
The TMTRAINER randomization is a reference to an old randomizer mod that came out before Afterbirth+^[1].
Unused enemies from Antibirth such as https://antibirth.fandom.com/wiki/Nightwatch, Corpse Eater and Barfy can appear int his challange, although its very unlikely..

Bugs

Bug!	This challenge is prone to crashing the program, either while running it or when trying to continue the challenge after quitting the program in the middle (even if it had seemed to be stable before that). If this happens it will probably be necessary to start a new playthrough. This may corrupt save data.

Bug!	If the challenge is able to be resumed after quitting, most (or all) of Isaac's items will be gone.

Bug!	If there is an effect that applies to spawned consumables, it will happen to the completion trophy, possibly causing completion to become impossible that run.