Dynomutt (basis prototype)
|Occupation||Oppressive Crime Fighter|
|Interests||Punishing anyone who breaks the law|
|Voiced By||Frank Welker|
After Dynomutt is severely damaged in battle, Blue Falcon seeks the aid of Dexter to save him. After repairing Dynomutt and witnessing his incredible stupidity, Dexter decides to shut him down and build a brand new canine sidekick from scratch, thus creating Dynomutt X-90. At first, Blue Falcon is none too pleased about the state of his companion, but Dexter tries to put his concerns to rest by showing how skilled and capable X-9 is at crime-fighting. At first he seems to be performing admirably, but, as expected from many a botched experiment Dexter makes, Dynomutt X-90 proves to be an exceedingly strict and violent enforcer of the law, forcing Blue Falcon to stop his "beloved friend". Dexter then dons his DexStar superhero persona and aids the Blue Falcon in shutting down X-90.
At first, Dynomutt X-90 proves to be too powerful for both heroes, and so Blue Falcon tries to reach out whatever is left of his former sidekick within the mechanical monstrosity. But just then, Dexter reveals that X-9 is not the original Dynomutt, who is still deactivated in the lab due to being a goofy idiot sidekick. Blue Falcon then reprimands Dexter, telling him that Dynomutt is more than just a goofy idiot sidekick, for he is "A Go-Go Dog Person!". Blue Falcon then uses a transmitter on his utility belt that sends out a distress signal that reactivates Dynomutt, who quickly travels to their location and is able to outwit his "successor" by posing as a cat, which X-90 begins to chase. He then shoots an explosive bone at X-90, briefly stopping the mechanical beast's rampage, and giving Dexter enough time to shut him down once and for all.
After his defeat, Dynomutt X-90's remains were placed in Dexter's Broken Dreams Vault where he keeps all of his failed and destroyed inventions.
- Dynomutt X-90's design is a reference to Friender, the robot dog companion of anime superhero Neo-Human Casshan