Choomba

Choombas are a kind of giant, metallic, locomotive-type Goomba found in the game Mario & Luigi: Bowser's Inside Story. Their name is a pun on "choo", a sound effect associated with train whistles, and "Goomba". They have coal-black bodies, red eyes, yellow-glowing pupils and a chimney on the top of their heads. Only Bowser can fight these enemies. They are associated with Coalbits, which will jump into a Choomba's head during battle to make it attack more and with greater speed. A Choomba will charge up its attack by walking back and shooting smoke out of its head showing either a shell or a fist; the smoke will appear in a different pattern each time. The patterns indicate the order and types of attacks it will use. The Choomba will then charge into Bowser, who needs to withdraw into his shell when Choomba jumps on him and needs to punch the Choomba when it runs into him depending on what command is shown in the smoke. Choombas also appear in the battle with the Fawful Express. Groups of four of them come out of the Fawful Express to attack Bowser. To counter this attack, the player must tap the area the Choombas are coming at Bowser and stomp them.

While Mario and Luigi cannot normally fight Choombas and explore the Tunnel in the original game, functional coding for an encounter can be discovered via cheats. When fought by Mario and Luigi, they had unique smoke signs that smoked an M for Mario and an L for Luigi, which can be countered with the Hammer, then the game proceeds to be softlocked after the attack is finished if a Coalbit jumps into the smokestack of the Choomba.

Bowser can use the Vacuum Block to inhale a Blitty from Choombas.

Choombas reappear in Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, where they also appear in the Bowser Jr.'s Journey mode as enemies. Rather then their puffs of smoke being a shell and a fist, they are instead images of the Choomba either running or jumping. Like other Goomba variants, Choombas are weak against yellow Shy Guys.

Mario & Luigi: Bowser's Inside Story / Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey

 * Bowser Jr.'s Journey profile: They charge forward with supreme confidence. Their attacks miss easily, but they don't mind. They take pride in their strength.