The 13th Dimension
The 13th dimension is commonly used as a scapegoat for the siblings when they have to explain character origins, one such notable character coming from them is Prince Fang. Some sort of inter-dimensional dragon that is allergic to rust.
Prince fang is, as his name suggests, royalty. He hails from the 13th Dimension and is part of the 19th dynasty. He has enslaved creatures from over 50 dimensions, making him one of the most evil creatures that Papa Acachalla and his family have had to fight. He followed Papa Acachalla home from the 17th dimension after he ate his wallet and took his kidneys. Sally and Gertrude both thought he was adorable, although, Papa Acachalla was able to realize his true evil. He then proceeded to make Acachalla's life a misery, taking from him the only things he cared about - his bed, food, toilet and TV remote.
Acachalla decided to do some research on him and discovered his true identity in a newspaper, but Fang ate it before he could show anyone. Finally he gave up and called in Spencer to help him get rid of it, but at some point he decided to "go in manually" to get his wallet, allowing Fang to eat him. Spencer revealed the true evil of Fang and threatened Fang with his one weakness: Rust. Spencer gave Sally six bullets fashioned from his braces and told her to kill the dragon, as it had eaten her waffles. She chased the dragon down and killed it, and just seconds later Sue arrived, proclaiming he was "here to kill the dinosaur" (In reference to Fang) and was promptly hired to retrieve Acachalla from Fang's intestines. It is also shown that, whenever he eats a turkey he will become Godzilla, and eating an owl turns him into Freddy Fazbear .
Jack Links is the adoptive father of Mary and is married to Susie Gumball. If what Susie says is true, Jack is actually a mermaid. He is the 13th dimensional equivalent of Papa Acachalla. Because of this, like every other character from the 13th Dimension who has an equivalent in Earth, his features are almost totally different from those of Papa Acachalla. In his case, almost all that Papa Acachalla does, he does in a similar fashion. For example, he is the adoptive father of two children, Mary and his "Owner" (whom Mary previously thought was his sister). The way he acts is quite similar to how Papa Acachalla acts, but not much is known about him, because there is still only a few videos with him. According to him, he knows who his equivalent is on Earth, and doesn't like him much. He thinks that all of the Acachalla Family is weird.
He apparently is not originally from the thirteenth dimension, but is a failed clone of Papa Acachalla which the original Acachalla Family imprisoned into the thirteenth dimension. I am simply putting him on this list because in all the videos we have seen him in, he has been there and as far as we can tell he lives there.