In I.B.F.F Diaries '14-Part 4, it's revealed Dynomutt is Scooby-Doo's cousin.
Scooby Doo, Mitchell, his friends and the Mystery Inc gang go for a visit at Scooby's cousin Dynomutt and Shaggy's uncle, Blue Falcon's residence. The friends spend time together, but it's not long before Mitchell, Becky and Templeton are kicked out. They are told by Radzi that Scooby is spending the week at Dynomutt's place. Dynomutt still retains his goofy personality, but has traumatic memories of seeing himself in robot form and in the Scooby Doo movie Mask Of The Blue Falcon, which is causing his major distractions in his day-to-day life. This version of Dynomutt has PTSD, which means he acts strangely whenever he remembers something that shocked him. The rest of the week shows how Scooby's stay at Dynomutt's house helps him with his PTSD, like when Scooby Doo goes to share a milkshake with his girlfriend Nova, Dynomutt becomes attracted to them, and when a gang of cats who once took Francine's cat under their wing force Dynomutt to watch Mask Of The Blue Falcon in front of a crowd of dogs, including Scooby, and then forced to fight his cousin as the Mystery Inc gang try to stop him. Eventually, they lead him in calm activities that help soothe his cousin's feelings, and by the end of the week, they leave Dynomutt feeling calm and happy again. This is followed by Mitchell and his friends asking Newsround to talk about PTSD in honor of Scooby's cousin.
