The Weegee Doll Invasion was an event the Luigi Dolls began taking over the Mushroom Kingdom in SM64 Bloopers: Luigi Labyrinth and SMG4: The Weegee Uprising, turning them into Luigi Dolls. It happened twice, with the second one being the longest, spanning over 500 years.
First Invasion (SM64 Bloopers: Luigi Labyrinth)
While Luigi was out getting spaghetti for his brother Mario, he decided to volunteer for a cloning science experiment. Feeling worried, Luigi brought a Luigi Doll with him despite the scientists' warnings, resulting in the doll becoming sentient and gaining the ability to transform anyone into a Luigi Doll by hugging them. Realizing he could control the dolls, Luigi became drunk in his own power and decided to turn the Luigi Dolls into a world-conquering army. Professor E. Gadd caught wind of this, but due to being on vacation, told Mario and SMG4 that if the situation wasn't stopped, they would have to live in a world full of Luigis.
After several run-ins with the dolls as well as creating a female clone of SMG4, the two found Luigi in an underground facility below the Science Lab and in the sewers. As Luigi chronicled his rise to power, however, he found that Mario and SMG4 were plating bombs around the place and not listening to his story at all. Using a Luigi Doll with a missile on its butt, Mario, SMG4, his minion, and Luigi escaped the exploding facility. As there wasn't a normal cure for everyone, they decided to sell the transformed citizens.
Second Invasion (SMG4: The Weegee Uprising)
While playing with Fishy Boopkins and Shroomy at Peach's Castle, Luigi's doll suddenly gained life and appeared in the corner of the foyer. When Luigi tried to retrieve it, it became Defective Weegee and attacked Toad, transforming him into a Luigi Doll. Apparently, the Luigi Doll was mad at humanity for their crimes committed against them, being treated as abominations, slaves, animals, and whatnot, and was preparing an uprising. Luigi, not wanting a repeat of the first invasion, fled with Boopkins and Shroomy to an ice cream shop, reluctantly leaving behind several of their friends in the process, including SMG4. Locking themselves in a freezer, they were frozen and would not come out until 500 years in the future. During that time, the Weegees proceeded to usurp the Mushroom Kingdom, transforming all the citizens into Weegees and killing those who posed a threat to them. E. Gadd's descendants tried working on time machines to stop the invasion from occurring, but the Weegees killed them before they could use it. New Super Duper Mario Plus Ultra, Mario's descendant, and Danny DeVito were the only survivors of the catastrophe.
Finally, during the 500-year anniversary of when they took over the kingdom (hosted by Hokage Weegee, a Weegee wearing a Hokage hat) in 2519, Luigi, Boopkins, and Shroomy were freed from their icy tombs and roamed the land that was once their kingdom. Hokage Weegee also stated that the day marked the end of Luigi, who was their oppressor and creator (which Shroomy called "one hell of a family reunion). Realizing their friends are all dead, the trio mourned them, but Luigi, wanting to be strong for Mario, said there must be a way out of this. Unfortunately, he ended up giving his position to the Weegees. The trio was saved by New Super Duper Mario Plus Ultra, who took them into his car and drove them to his hideout. Luigi could tell he was related to Mario due to his love for spaghetti and eventually told him what happened before.
NSDMPU told the gang about how E. Gadd's descendants tried to build a time machine back to 500 years ago but failed, resulting in the E. Gadd Labs building being overrun with Weegees. They, however, had a plan: Luigi would pretend to be a Weegee, have Boopkins sing a terrible song that would distract the Weegees, and while this was happening, Luigi would allow the rest of the gang into the building, and then they would use the time machine. The plan worked, but upon activating the machine, the Weegees discovered what was going on and tried to break into the time machine room. While NSDMPU held the army off, Luigi, Shroomy, and Boopkins were sent back to 500 years ago, but not before Luigi stated that he would remember NSDMPU as his future grandson was killed by the Weegees.
After being sent back to 2019, the trio stopped Defective Weegee from attacking Toad and pinned it on the Bob-Omb Battlefield room, where it explained its reasons for wanting to usurp the kingdom. Before it could go any further, Shroomy grabbed a shotgun and destroyed Defective Weegee with it, returning everything to its previous state and erasing the bad future timeline.