The Dark Beacon is a special beacon made by the Dark Star in the final room. It disables the abilities of the heroes, as well as contains any corpses of the fallen heroes for Necrola to turn into Killer Robots, and for Flowey the Flower to absorb the SOULs from. According to Flowey, he has to fix it every time it gets broken.
- The following characters are unaffected, due to lacking abilities:
- Script has lost some of his knowledge.
- Me has no more psychic powers, but still can reincarnate.
- GLaDOS is unaffected, due to her personality core being at room 21.
- Barbarian King cannot use Iron Fist.
- Super Monkey is depleted of his spikeballs.
- Sans the Skeleton cannot summon Gaster Blasters.
- Star's wand has low energy, causing her spells to be duds. She also can't use her Dimensional Scissors.
- Marco becomes far clumsier. (This is odd, since he's a normal human.)
- Voltaire cannot use Plant Food. In addition, her electric powers are weakened.
- Rosalina cannot teleport.
- Gruffle's toxic effect is disabled.
- Papyrus' bone attacks are disabled.
- Tom the Toxic Pea cannot use toxins.
- Mewtwo's powers are weakened.
- Marcy is now a human.
- Angris cannot be angered.
- President Toilet cannot be cloned.
- Milo's law turns against him, causing bad things to happen to him only.
- Sonic the Hedgehog has been reduced to other characters' speed.
- P.E.K.K.A does less damage with his sword.
- Mini Pekka is slower.
- The Aerielbots and all combiner teams cannot combine.
- Lucas' Cute Fishron is not affected when wet.
- The Mysterious Figure is also unaffected by the beacon, but it's because Dark Star wasn't expecting him to return.
- ☟☜☹☹⚐📬 will also be unaffected by the beacon, because he joined in late.
These are effects that would happen to characters had they been introduced at the time.
- The following would be unaffected:
- Spyro wouldn't be able to use any breath runes aside from Fire.
- Jaiden, CypherDen, and Rebecca won't be able to use their elemental ninja powers.