20K Boss Rush

The 20K Boss Rush was the finale of the Re: Glitch Arc. Immediately following The Pause, ▶▒ A▒ pulled J-Team members in and out of a series of pocket dimensions in which they had to fight a gauntlet of previous opponents, ending with ▶▒ A▒ itself.

The 20K Boss Rush began on the RP's 6th anniversary, and ended on Page 20000, hence the name.

Major Differences

The incarnations of each boss in the 20K Boss Rush were not always perfectly identical to their original battles; sometimes the differences were minor, sometimes they completely changed the course of the battle.

Constantin and Shaka

• 20K!Constantin ended up opening the Fourth Gate in his battle, effectively incinerating himself in a last-ditch effort to destroy everyone else. The real Constantin never did such a thing, and is currently still alive.

Shadow Heatran (Resources Building Meltdown)

• The original scene was relatively short, with Ellen doing little more than scavenge for whatever documents she could from the Resources Building before using Phantom Force to escape. In the 20K version, the J-Team had no such teleportation ability, and had to rush through the building with Shadow Heatran quite literally hot on their trail, systematically destroying each room. In both situations, attempting to fight Shadow Heatran proved fruitless.
• In the original, Shadow Heatran's method of destroying the building was more or less generic lava-based melting, seen only from outside. In the 20K version, it used a unique technique to systematically Disintegrate the place one room at a time.
• Uniquely, Paula was the only non-Glitch antagonist to be aware that she was living in a recreation of the original event rather than the real thing.

Penumbra

• Penumbra was mostly the same, but had an expanded movepool due to more Ghost-types existing in the franchise than during the Conquest arc. Namely, Penumbra used King's Shield, signature of Aegislash.

Sister Grimm

• The original Sister Grimm transformed itself into a hybrid of a Mismagius and a Rayquaza; in the 20K version, the existence of Mega Evolution allowed her to use Mega Rayquaza in her hybrid instead.

Seven Jerk Dragons

• The original RtAU arc never concluded onscreen, so the 20K version gave indirect resolution to the arc.

Annoski

• No significant differences beyond participants.

Lanius

• No significant differences beyond participants.

'M

• Initially, it appeared that, like before, the J-Team would have to battle 'M twice to destroy both cores; however, 20K!'M's data core was a fakeout, and instead the room collapsed and turned 'M into a hybrid of both his data core and his organic core.
• 'M was not destroyed by the J-Team; instead, ▶▒ A▒ cannibalized him before he could deal a final attack to gain strength for the true final battle.
• 'M didn't godmod in the 20K fight, regardless of whether he was capable of doing so or not.

▶▒ A▒

• ▶▒ A▒ was intended to be the equivalent of Missingno in the fight, but quickly diverged into its own character.
• ▶▒ A▒ constantly shifted between forms of other old J-Team fights for each turn of its battle, including the Deoxys Horde, Queen Sectonia, The Administrator, the Stormchaser, and the Dream World Crash.