Tesseract's Cat was the cat owned by the assassin Tesseract. Before he died, he told Skulduggery Pleasant that he had a cat with no name; it was just called "cat". He said he would miss it. Skulduggery replied that he knew about the cat as Tesseract had cat hair on his lapel on the day he killed Davina Marr. Tesseract then said You really don't miss much, do you?
After his death his cat was taken in by his neighbour, but not much was revealed after that.
- A question asked with an interview with Derek Landy was what happened to Tesseract's Cat he replied saying His neighbour is minding it.