|Voiced by:||Troy Baker|
|First appearance:||"The Button"|
|Latest appearance:||"Welcome to Space (cameo, video)"|
Dr. Reuben Langer is a supporting character in Regular Show. He is a scientist, who helped put the dome on the park for the second time. Initially his primary goal was to usurp the position of park manager from Benson for unknown reasons, but he mainly stays to test all of the Park members, and eventually sends them into space.
In reality, he's one of Earth's operative of Space Tree Intergalactic Official's branch to operate the main characters' preparation to protect and awaken Pops' true potential as the Chosen One against a dangerous outcome lies above them, who is none other than Pops' brother Anti-Pops.
He first appeared in "The Button".
He is a partially balding man, age ranging from middle-aged to elderly. He is almost always seen in a lab-coat and jet-pack, while sporting an eye-patch on his left eye.
He is introduced in "The Button" being the one to reveal that the dome experiment was back on. From that day forward, he continues to lead the scientist's experiments through the park, spearheading many rules much to the annoyance of the park workers.
At one point, he was intimated by Benson threatening him for his employees to have a certain requirement and he complied. He has been testing for some time, the test finally being concluded when all the park employees pressed the button launching them all into space. The reasons for was because of Pops' true origin and Anti-Pops' quick movement.