The Green Harpoon is a light blue fish with lavender lips who, when he was younger, had light brown hair and a light brown soul patch. He wore a black mask and a medieval-styled costume stereotypically associated with archers, which features a light green shirt with a green vest and two gold buckles, green leggings, brown gloves and boots, and a triangular green cap with a red feather. He always carries a green harpoon with a small loop at the end for string to go through.
When he got older, he lost the hair on his head and his beard became longer and white with age. His mask is now smaller and thinner (similar to Barnacle Boy's mask) and the red feather on his cap has lost all its barbs, leaving the bare rachis of the feather. His lips are also slightly wrinkled.
Powers and abilities
The only known superpower that the Green Harpoon has is that he can shoot green energy beams from his harpoon's barb. The comic implies that he has more powers, but SpongeBob notices that the Green Harpoon has disappeared just as he was about to talk about his abilities.
Role in comic book
In the comic Lo, There Shall Be A Catered Affair!, he and the rest of the Aquatic Adventurers meet together at the Krusty Krab for their 75th reunion. When the Flying Fish is pulled in to Mr. Krabs' office to sign Mr. Krabs' copy of Aquatic Adventurers No. 1, SpongeBob, the Green Harpoon, and the rest of the Aquatic Adventurers notice his absence.
SpongeBob compares the situation to the story in the team's comic book, where they are attacked by the Invisible Isopod. The team is skeptical at first, but the Green Harpoon and the rest of the team start believing SpongeBob when Barnacle Boy goes in Mr. Krabs' office.
When the team notice Lighthouse Lass' disappearance, they start to panic, but SpongeBob reminds them that they have powers. He goes to remind the Green Harpoon about his powers, but he notices that the Green Harpoon has disappeared (as he is signing Mr. Krabs' comic book). When SpongeBob is scared by a mailman after the Green Harpoon vanishes, he states that the team should hide somewhere that they can't be surprised, and the Green Harpoon comes back in time to hide in the bathroom with everyone else.
When Mr. Krabs opens the bathroom door while looking for everybody, SpongeBob orders the Aquatic Adventurers to attack, with the Green Harpoon shooting a beam of energy that zaps Mr. Krabs. He and the rest of the team realize their mistake, and bemoan how the Invisible Isopod wasn't attacking, as it thrilled them. He then watches in shock as Barnacle Boy is wedgied by the Invisible Isopod.
The Green Harpoon then appears in a bonus gallery poster later in the same comic book, alongside nearly every other Mermaid Man hero to exist.