Boss Bass

A Boss Bass is a giant Cheep Cheep that often patrols the surface of the water. It is also found underwater, where it is called Big Bertha. Boss Basses and Big Berthas are the original "giant" counterpart to the jumping and swimming Cheep Cheeps, respectively, though this role is currently held by Big Cheep Cheep, which is only found swimming in most platforming games. Their voracious nature is given to Cheep Chomp, another occasional giant counterpart to Cheep Cheeps, which was redesigned to resemble Boss Bass in Super Mario 64 DS and even has the same behavior and English name as Boss Bass in Yoshi's Island DS.

Super Mario Bros. 3
In Super Mario Bros. 3, the Boss Bass swims on the water's surface in Worlds 3-3 and 3-8, trying to leap out and eat Mario if he gets too close. It defeats Mario instantly in one gulp regardless of his form. In both of the stages it appears in, the water level rises and sinks, making Mario an easy target. Throwing blocks, shells, hammers, and fireballs at the Boss Bass can defeat it, as well as tail attacks and using a Starman, but it eventually comes back. However, in Super Mario Advance 4: Super Mario Bros. 3, if the player has turned on the e-Reader card that makes enemies hit by fireballs turn into coins, and the player successfully hits the Boss Bass with a fireball and collects the coin, the Boss Bass does not return for the rest of the level.

The passive Big Bertha is found swimming back and forth underwater in Worlds 3-5, 4-1, 6-9, and 7-4, carrying Baby Cheeps in their mouth, and occasionally letting them out. After a few seconds, the baby returns to its parent's mouth.

In the credits, in World 4 there's new sprites of Boss Bass and Mario.

The Adventures of Super Mario Bros. 3
Boss Basses make appearances in The Adventures of Super Mario Bros. 3, where they usually chase after Mario and his friends.

Nintendo Comics System
Bertha, a character influenced by the Big Bertha species, plays a prominent role in two Nintendo Comics System stories. In her first appearance, Love Flounders, she falls in love with Frog Mario after being tricked by Stanley the Talking Fish. She eventually realizes Stanley was lying, but is consoled by Mario, who states he wants to be friends with Bertha, not lovers. Bertha later reappears in Fins and Roses, this time dating Stanley. She foils Wendy O. Koopa's plans by knocking the Koopa's bomb back at her.

Mario Teaches Typing
In the second mode of Mario Teaches Typing, Underwater World, the game repeatedly loops footage of Mario, Luigi or Princess Toadstool swimming away from either a Boss Bass or a Blooper. Their appearance is slightly different: their fins are cyan, they have several sharp teeth rather than a single blunt tooth, and have round pupils with eyebrows instead of squinting pupils.

Super Paper Mario
In Super Paper Mario, Boss Basses do not appear but are given two passing mentions in the English script. In The Underwhere, a Shayde tells another one of three stories about how he lost a life. The second story involves him falling into the sea from a pipe, but instead of drowning, he can apparently swim as well as a Cheep Cheep. However, a Boss Bass thought that since he swam like a fish, he was one himself, and the huge fish ate him. In the Japanese version, a shark is mentioned instead. The other mention of a Boss Bass is via the 77th Sammer Guy Ripper Van Fish, who mentions counting Boss Basses to sleep if spoken to after defeat.