Tack (Right) and his subordinate (Left)
Story[]
Tack is the leader of a gang, and appears as a guest character in episode 4: "Goodbye, little brother!"
He made a robotic dog to try to destroy Jetter Mars. The Robotic Dog is adopted by Jetter Mars, who calls the dog his little brother.
The Puppy was never given a name from Mars, Mars always just called him "Brother" or "Little Brother." Little Brother was a Puppy Mars saved from becoming roadkill, in the process having to knock Dr. Yamanoues car off the road. They are then attacked by a tank, Mars ends up blackmailing Dr. Yamanoue into keeping the puppy. Dr. Yamanoue ends up saying yes, and Jetter Mars saves him.
Mars playing with his new brother!
Mars consoling his brother.
Mars gets really attached to this puppy, Dr. Kawashimo ends up worrying about the tank that attacked Dr. Yamanoue, and convinces Dr. Yamanoue to inspect the Puppy, the Puppy attacks Dr. Yamanoue, who then found out that the Puppy was a robot, and tell Mars to destroy it. Mars panics and tells Dr. Yamanoue that he won't do it and that it's his brother! Mars consoles the puppy, and they run away.

Mars' little brothers inner-workings.
Dr. Yamanoue and Kawashimo analyze a projection of the mechanical inner-workings of the puppy, finding that there's a bomb inside it. Just then they're attacked by a group of gangsters led by a man named Tack. They blackmail them into giving the puppy back to them. So they go to Jetter Mars and try to take the puppy and remove the bomb before the gangsters arrive, but the gangsters attack them, threatening them that if they don't put the puppy into the flying vehicle that they will activate the bomb. Mars can't take this, and goes in with the puppy, thinking that he wouldn't risk blowing up the pod with Tack inside it piloting. However, it's revealed that inside the pod is a dummy with a speaker!
But, just before the puppy explodes though, he pushes Mars out of the pod, and detonates. Dr. Yamanoue can't take this, and deletes that part of Jetter Mars memory. Jetter Mars can still remember having a little brother at some point though...
Jetter Mars recognizing he might of had a little brother at one point.
Trivia[]
The episode Jetter Mars' little brother appears in is strikingly similar to the episode of Kirby: Right Back at Ya's 15th episode "Kirby's Pet Peeve" or: "Birth? Kirby's Little Brother, "Tanjō? Kābī no Otōto" (誕生? カービィのおとうと) " Where kind DeDeDe makes a robotic Dog for Kirby that will explode in a couple days, the exact same thing happens with the pod, Kirby seems to move on, seeing the dogs shape in the stars. (The episodes air date is January 12, 2002, so it proceeds the air date of this episode being February 24, 1977)