A ghost invasion is when the spirits of those who have passed encroach upon the Earth en masse. Such a supernatural onslaught can be the Big Bad's plan, a side effect of said plan, or a regularly occurring event (often on or around Halloween).
Compare Alien Invasion, Hell on Earth, and Zombie Apocalypse for similar, otherworldly events and trespassers. Cavalry of the Dead is similar, but those dead are usually good guys, not neutral or evil. Not to be confused with Legion of Lost Souls, which is about the French Foreign Legion.
- Final Fantasy: The Spirits Within: Earth is attacked and nearly destroyed by an alien race known as the Phantoms, who can turn invisible, intangible, and destroy human souls. However, Dr. Aki Ross discovers that the aliens are in fact genuine ghosts who died during a civil war on their planet. When a piece of their homeworld crashed into Earth, their confused and tormented spirits wreaked havoc on the unsuspecting humans.
- The Sandman: After Lucifer evicts the residents of Hell and surrenders the key to Morpheus, the ghosts of the damned haunt the Earth en masse. However, all we see on the mortal side of things is a British boarding school filled with former staff and students, but the living staff pretend that things are perfectly fine.
- Wonder Woman (2011): After the First Born kills Lord Hades, the shades of Hades flood the surface, where they drift listlessly everywhere among the living.
- Ghostbusters (1984): Ivo Shandor, the architect of Dana's apartment building, designed it to channel ghosts for the purpose of ending the world. As a result, paranormal activity increases all over New York. Later on, Walter Peck forces the authorities to shut down the Ghostbusters' containment grid, causing all the ghosts they captured to be unleashed on the city.
- Ghostbusters (2016): Rowan North, the film's Big Bad, kills himself so he can become a powerful ghost and command an army of spirits to bring about the apocalypse. North possesses the Ghostbusters' secretary Kevin and opens a portal that releases hundreds of ghosts on New York City.
- The Problem in Lockwood & Co. is Visitors (ghosts) returning and causing all sorts of trouble. As a result, many ghost hunting agencies were set up to deal with the problem.
- The Shades in Shadows for Silence in the Forests of Hell are ghosts with a Hair-Trigger Temper. They attack anyone who breaks their three rules: "Don't kindle flame, don't shed the blood of another, don't run at night". Only silver can protect you from enraged Shades. There are plenty of ways to get around these; running is the least dangerous, bleeding through accidents is safe, killing in ways that don't shed blood is safe, and lighting a fire using another flame is also safe. Silence's inn has a fireplace that hasn't gone out since it was lit.
- This was the bad guys' plan in Warrior Cats: Omen of the Stars, as they were already dead. They had to learn to take on physical form, however, because otherwise they couldn't interact with the physical world.
- Doctor Who: In "Army Of Ghosts", the Doctor and Rose discover that "ghosts" are now a common occurrence all over the world. They appear at specific times to walk among the living and are welcomed with open arms by the public, but the Doctor and Rose think it's horrifying and want to figure out what's going on. It's ultimately subverted. These aren't ghosts, but Cybermen trying to break out from a different universe. People allowing the Cybermen to walk among them as "ghosts" inadvertently allowed for a Cyberman invasion.
- Kamen Rider Ghost features "Gamma" spirits attempting to cross over from their own realm to take over Earth. But it's played with when it's revealed that the Gamma are really still-alive Human Aliens using Magitek to separate their souls from their bodies.
- This is the start of Chuck's plan against the Winchesters and the world in the last season of Supernatural, letting the souls out of Hell and allowing them to attack the earth en masse. This phase only really lasts for a couple of episodes, but ending it requires the death of Rowena.
- In Ghostbusters: The Video Game, this is the entire plot. Ivo Shandor, deceased architect of the events of Ghostbusters (1984), not only built the high rise near central park; he built a mandala out of several New York landmarks, including the Sedgwick Hotel and the Central Library. A series of underground tunnels channeled spirits from site to site, ending at Central Park. The end result is several locations completely overrun by spirits, and the barrier between the spirit world and the real world weakened until some areas were transformed.
- Luigi's Mansion: Dark Moon: In the level "Paranormal Chaos," King Boo activates a portal that brings waves of ghosts from another world into Evershade Valley.
- Moshi Monsters: One of the plots involved the ghost of Dr. Strangegloves severed hand opening up a portal to another dimension, leading to an influx of ghosts entering the main universe and, among other things, locking Tamara in her lab.
- The 13 Ghosts of Scooby-Doo: Weerd and Bogel, the main villains, released thirteen ghosts from the Chest of Demons (stored in Tibet). It was a Race Against the Clock for Scooby, Shaggy, Scrappy, Daphne and Flim-Flam to get them back.
- Ben 10: Omniverse: In the flashback episode "From Hedorium to Eternity," Zs'Skayr possessed the body of Thaddeus J. Collins and attempted to take over Earth by having his fellow Ectonurites possess people, as well.
- Danny Phantom: While it could be argued major ghost assaults are the entire premise of the series, there a few notable instances of such:
- "Public Enemies" features Walker launching the first major mass ghost attack on Amity Park, definitively revealing the existence of ghosts to the world in the process.
- Reign Storm: The arrival of ghost king Pariah Dark causes all the ghosts in the Ghost Zone to flee to Earth. The Ghost King's armies also invade.
- The Real Ghostbusters: In the episode "You Can't Take It With You," a dying billionaire builds a machine to open a portal to the afterlife so he can take his vast fortune with him. Unfortunately, this causes a rupture in the separation between the human and spirit worlds, causing ghosts to invade the land of the living.