Those alien beings originated from a location known as "Trilazzx Beta". They can exist in seven to eleven dimensions at once, and are known for their "horrible sense of direction."
30 million years prior to the events of the series, a group of Trilazzx Beta Aliens crash-landed their spacecraft, creating the valley that would one day host the modern-day town of Gravity Falls, Oregon, as well as forming the bizarre floating cliffs surrounding the land. As time passed, the surviving crew died off while their ship was buried beneath the surface.
Long after, it was discovered by both Ford Pines and Fiddleford, who studied their technology and language, as well as used some of the parts to build the Universe portal.
Powers and Stats
Tier: At least 1-C, Likely High 1-C
Name: The real name of the species is unknown, but they are called by the names: "Trilazzx Beta Aliens", "Extraterrestrials" and "Pan-Dimensional Beings"
Origin: Gravity Falls
Gender: Unknown, Likely varies (They're an entire species)
Age: Unknown, They all died over 30 million years ago
Classification: Aliens, Higher Dimensional Beings
Powers and Abilities: Unknown, Likely Higher Dimensional Manipulation
Striking Strength: At least Complex Multiversal, Likely High Complex Multiversal
Range: 7 to 11 dimensional
Standard Equipment: A spaceship full of alien technology
Intelligence: Unknown, Likely Supergenius (The technology in their ship is vastly superior to anything humanity is capable of building)
Weaknesses: Poor sense of directions when they're traveling in lower dimension. Featless
Note: All the Trilazzx Beta Aliens presented in the show are currently dead due to their ship's crash.