Beef

Beef is a member of the Best Fitness Friends and a major antagonist in the Bowser Jr. portion of the Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey storyline. He is a muscular creature with pink skin, several layers of either muscle or fat, and red hair. He acts as the group's brawn (being the Melee typed fighter in battles). Much like Kaley, another member of the BFF, Beef derives his name from a type of highly nutritional food; "beef" is also a slang term for muscle.

He is first encountered with the other members of the Best Fitness Friends, and seemingly defeats Ludwig alongside Iggy a bit later on.

However, it is revealed that the situation is not what it seems. Instead, it is revealed that Ludwig had defeated Beef in their encounter, and had been disguising himself as him the entire time. The real Beef was chucked into lava early on, and left in the storage room back at Bowser's Castle afterwards.

After that though, he returns to the other Best Fitness Friends for their next encounter outside of Bowser's Castle (where he's battled) as well as with them in the final battle. Here he merges with Kaley and Dieter to form the final boss, before eventually being defeated for good.

Profile
Beef ''The brute force of the BFF. He's silent, but just one attack will leave you reeling.''

Trivia

 * Beef is the only member of the Best Fitness Friends that makes a cameo appearance in the main story as he is added to the Bob-omb storage room scene, where he appears unconscious.