Hook, Line, and Sinker are a trio in a long line of Unicron minions.
Marvel comics continuity
Instead of killing the criminals, Unicron reformatted them into three powerful assassins, whom he named Hook, Line, and Sinker. Each was given new weapons: Hook (not to be confused with the Constructicon of the same name) has a hook on one of his hands and a harpoon on the other, Line carries a sword and a net, and Sinker has two massive steel balls at the end of his arms.
Hook, Line, and Sinker's first mission was to fetch Galvatron from an alternate timeline, where the Decepticons had defeated the Autobots circa 2009. Galvatron was leading the Pretender Monsters onto a final victory march into New York City, when Hook, Line, and Sinker captured him and brought him to the "real" timeline, circa 1991.
Unicron intended Galvatron to serve as his chief assassin and Hook, Line, and Sinker to serve as Galvatron's aides. The four powerful creations assaulted Autobase. But, when Galvatron met Emirate Xaaron deep under the surface of Cybertron, he rebelled against Unicron and (at least apparently) sided with Xaaron instead. Unicron was unable to perceive what Galvatron was doing while inside Cybertron and immediately dispatched Hook, Line, and Sinker to retrieve Galvatron. Not having surprise on their side this time, the trio failed, with Galvatron destroying two of the trio and Primus disposing of the third.
- Although Hook, Line, and Sinker have never been represented as toys per se, the Club exclusive toy representing Astrotrain from the Unicron Trilogy includes three Mini-Cons named Astro-Hook, Astro-Line and Astro-Sinker. However they do not have any apparent connection to Unicron, or at least not more than any other Mini-Con.
- It is intriguing that Unicron should choose a quaint Earth saying as the basis for three of his most dreaded heralds.