From the Super Mario Wiki
Mecha-Bloopers are rare mechanical Blooper enemies that appear in Mario & Luigi: Superstar Saga and its remake, Mario & Luigi: Superstar Saga + Bowser's Minions. They only appear in battle alongside Cheep Cheeps (Spiny Cheep Cheeps in the remake) or Starkisses, found in the Oho Ocean Seabed and the underwater portions of Gwarhar Lagoon.
Their only method of attack is firing several Bullet Bills at Mario and Luigi. A Mecha-Blooper has a total of five Bullet Bills to shoot, and can fire off any number of them during an attack. If a Mecha-Blooper is attacked but not defeated, a "!" will appear above it and will automatically counterattack. However, once all five have been fired, the Mecha-Blooper must spend a turn to reload. They are especially vulnerable to Luigi's Thunderhand.
In Mario & Luigi: Superstar Saga + Bowser's Minions, the Bullet Bills they shoot are the only examples of Bullet Bills in the game that are not updated to resemble the current Bullet Bill design.
Mario & Luigi: Superstar Saga / Mario & Luigi: Superstar Saga + Bowser's Minions
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