|Rarity||Very Rare in water levels (may have a chance to appear)|
|Average Behavior||Eats people respectively|
|Habitat(s)||Caves in seas rarely|
|First Appearance||Super Mario Bros.: The Popstar Crossover|
|Latest Appearance||Super Mario Bros.: The Popstar Crossover|
It's appearance is similar to that of the Cheep-Chomp from NSMB, except different, it is larger in about the size of a medium submarine. It has a green fin shaped as a mohawk, their teeths are more square-ish and flat-ish. And is actually light purple instead of the color of a actual Cheep-Chomp.
This enemy makes it's debut in this game, they only appear in sea levels. To prove they are on sea levels is to see the marks of their face above the level mark. They appear near checkpoints and takes 9 hits to defeat them, upon defeating them, they will release a Toad or any other shopkeepers, if the player fails to kill it, it will flee to another underwater level.
- It is one of the strongest enemys counting up to 9 hits in Super Mario Bros.: The Popstar Crossover.
- Somehow, their green fins move a little faster if hit with a projectile/object.
- It is named after a Piranhacus Giganticus, except the Giganticus is at the first and Fishicus is at the end. It similarly appears like a Nabbit appears when three levels is complete when not caught, but only in underwater levels when they have a chance of appearing when enemy courses are beaten.