What is the Tesseract in the Doctor Who universe and what purpose does it serve?

In the Doctor Who universe, the term "Tesseract" is associated with a comic book series rather than a specific object or concept like in the Marvel Cinematic Universe. The Doctor Who: Tesseract is a graphic novel that compiles two stories involving the Tenth Doctor and his companions Emily Winter and Matthew Finnegan. The stories include encounters with an Acari ship merging with the TARDIS and a plot involving living trees in Greenwich Park.

Key Points:

• Storyline: The graphic novel includes two main stories: "Tesseract" and "Don't Step on the Grass." In "Tesseract," the Doctor deals with the aftermath of a collision between the TARDIS and an Acari ship, while in "Don't Step on the Grass," he faces a threat from living trees and an ancient order called the Knights Arboretum.
• Purpose: The Tesseract in this context serves as a title for the compilation of these comic book stories, rather than a specific object or device within the narrative. It highlights the adventures of the Tenth Doctor with new companions and explores themes of time travel and alien encounters.

The term "Tesseract" itself does not refer to a specific object or device in the Doctor Who universe; it is more of a narrative title for these comic book stories.