Big Bully

Big Bully is a boss variant of the Bully. Two of them appear in Lethal Lava Land. They are boss variants of the Bully, acting exactly the same. One can be found regular on the map, and the other spawns after defeating 3 regular Bullies. A variation known as the Chill Bully appears in Snowman's Land. Another variant appears in the DS remake, known as Chief Chilly, unlocking Wario as a playable character when defeated.

Dialogue
Reportedly, the Big Bully has dialogue when Mario encounters him, much like the other bosses found in the game. So far, every report has shown empty text boxes, implying that the lines were cut much earlier on than other unused dialogue. It's possible that these lines were repurposed for Chief Chilly in the remake.

BackDown
Much like their smaller counterparts, the Big Bully has an unused kicking attack referred to as "BackDown" internally. After hitting the attack, the laugh it produces is deeper in pitch compared to the enemy version.