Scutlet (boss)

Scutlet is a tick-like creature inside Bowser's stomach, in Mario & Luigi: Bowser's Inside Story. It prevented Bowser from breathing fire by blocking a hole inside his body, which produced the fire. The Mario bros. investigated, and discovered Scutlet, who then ate Starlow. They fight with Scutlet to allow Bowser to breath fire and to free Starlow. In battle Scutlet has three attacks. One attack involves Scutlet sticking out its tongue in hopes of eating one of the heroic plumbers; the way its eyes point is a sign about who it shall attack, and its tongue can then be dodged with a jump. In the next attack, it wraps its tongue around Starlow and throws her in the air in an attempt to hit Mario or Luigi; this is countered by a hammer swing. Finally, Scutlet gets ejected into the air by Bowser's flame breath, and drifts down towards either Mario or Luigi; this can be jumped over, causing no harm. Once Scutlet is defeated, Starlow is set free and Bowser can breathe fire again.

Later in the game, more Scutlets appear outside of Bowser's body. For the full sized Bowser and Mario bros., it's trivial to defeat these.

Trivia

 * In the Japanese version of Mario & Luigi: Bowser's Inside Story, the boss version of Scutlet and the enemy version of Scutlet were different creatures.