While some television shows are set in the same universe, such as Frasier and Cheers or the Arrowverse shows, most take place in their own fictionalized worlds, making the appearance of characters from other shows unexpected and exciting. When done improperly, a crossover can feel like a cheap gimmick, but successful crossovers are a fun way to give the viewer a unique watching experience.
The most unexpected crossovers are those that occur between shows that have drastically different established tones, settings, or genres. But mixing characters from very different shows can bring out the best from both shows and create a one-of-a-kind story.
Power Rangers & Teenage Mutant Ninja Turtles (6.6)
In the Power Rangers in Space episode "Shell Shocked," the villainous Astronema brainwashed the Teenage Mutant Ninja Turtles and used them to attack the Power Rangers. After the Turtles break free from the spell, they team up with the Power Rangers to defeat Astronema before returning home.
For kids of a certain generation, there are no bigger crime-fighting teams than the Power Rangers and the Teenage Mutant Ninja Turtles. Cheesy as it may be, seeing the two squads share the screen and even fight against each other is an undeniably nostalgic experience.
Boy Meets World & Sabrina The Teenage Witch (7.2)
As part of a TGIF evening of crossovers that involved Sabrina the Teenage Witch, Boy Meets World, and the strange forgotten series You Wish and Teen Angel, Sabrina's cat Salem swallowed a Time Ball which caused the characters from these shows to be transported to different time periods. In the Boy Meets World episode "No Guts, No Cory," the group was sent back to World War II.
While the other shows all deal with magic or fantasy elements, Boy Meets World is a fairly grounded teen dramedy, making this crossover a change of pace from a normal episode. While it is not the best episode of the show, it does play to the show's greatest strength by focusing on Cory and Topanga's relationship.
Sleepy Hollow & Bones (7.6)
Despite both playing off of an odd couple dynamic, the Fox shows Sleepy Hollow and Bones use fairly different tones to their storytelling. The two shows crossed over in a two-episode event that saw the Sleepy Hollow characters meet up with the team from Bones to investigate a 200-year-old headless corpse.
As unlikely as it may be, these two shows work surprisingly well together. While the supernatural elements are pretty out of place for Bones, the dynamic between the four central characters works really well and makes for a fun, Halloween-themed experience.
The Fresh Prince Of Bel-Air & The Jeffersons (7.6)
In The Fresh Prince of Bel-Air episode "Will Is From Mars," Will and Lisa go to couples counseling, where they realize their problems are nothing compared to those of some of the other couples, including George and Louise "Weezy" Jefferson from The Jeffersons.
Seeing the actors return to their iconic roles is thoroughly entertaining, and they do not miss a beat. Despite being one of the best sitcom spin-offs ever, The Jeffersons never really got a proper finale so seeing the characters appear once more was a treat. The Jeffersons also returned for the Fresh Prince of Bel-Air finale, along with the characters from Different Strokes.
Phineas And Ferb & The Avengers (8.3)
While Disney has produced several animated Marvel television shows, it was still surprising to see the iconic characters crossover with Phineas and Ferb in "Phineas and Ferb: Mission Marvel." After the Avengers lose their powers, they turn to Phineas and Ferb to help them bring down a team of supervillains.
Surprisingly, "Mission Marvel" is actually one of the best episodes of the show. Phineas and Ferb bring their signature wit and humor to the world of superheroes. The gag of the heroes getting their powers switched up, the villains thinking Dr. Doofenshmirtz is a genius, and the boys naming their shed the Secret Hideout for Emergency Defense are especially funny.
Archer & Bob's Burgers (8.3)
Voice actor H. Jon Benjamin plays the lead character on both Archer and Bob's Burgers, but the shows are very different tonally and stylistically. This made the crossover between the two in the Archer episode "Fugue and Riffs" so surprising and entertaining. The episode connects the two shows by making Bob an identity that Archer assumed while experiencing amnesia.
H. Jon Benjamin is great as Bob and Archer but he essentially gives the same performance as both characters so making them the same person is a hilarious creative choice. Additionally, seeing the Belchers rendered in Archer's animation style is odd and funny as well.
X-Files & COPS (8.5)
In the event titles "X-Cops," the shows X-Files and COPS formed one of the most unlikely yet successful crossovers in television history. It would be hard to find two more different shows than the docuseries about real law enforcement and the fictional series about aliens.
The episode surprisingly works, thanks in large part to the smart writing and visual presentation. The episode is filmed in the style of COPS occurring in real-time and shot on videotape. The realistic look mixed with the supernatural elements results in one of the best episodes of X-Files ever.
I Love Lucy & Adventures Of Superman (9.0)
While there have long been guest stars on television, one of the earlier examples of a crossover came as George Reeves appeared in character as Superman in the I Love Lucy episode "Lucy and Superman." The episode only refers to the character as Superman, rather than George Reeves.
The episode is an all-time classic as these two icons share the screen. It also contains one of Lucy's best moments as she ends up stranded on a ledge while pretending to be Superman, forcing him to rescue her.
ALF & Mr. Robot (9.1)
In one of the strangest crossovers ever, 80s sitcom star ALF appeared on a season 2 episode of the drama Mr. Robot. While in a coma after a beating, Elliot dreams about a sitcom-style road trip, including an encounter with alien life form Gordon Shumway.
Mr. Robot has never been limited by conventional storytelling, but this fantasy episode takes the bizarreness to another level. It is an incredibly well-written episode that keeps the audience guessing. It is a completely unexpected crossover but it works within the framework of the elevated reality in which Mr. Robot takes place.
Supernatural & Scooby-Doo, Where Are You! (9.6)
"Scoobynatural" is a season 13 episode of Supernatural in which the Winchesters are sucked into an episode of the animated classic Scooby-Doo, Where Are You! But the Winchesters realize that the episode is not playing out as normal and must stop an actual ghost who is killing people in the episode.
As odd as the crossover may be on the surface, it actually makes a lot of sense. Supernatural lends itself to wild situations and the Mystery Inc. gang are used to dealing with ghosts, just not the real ones. It is a fun and nostalgic adventure that is equally fun and entertaining.