Bully

Bullies are a race of creatures that are first found in Lethal Lava Land in Super Mario 64 and Super Mario 64 DS, and have since become recurring, albeit occasional, enemies in the Super Mario series. Their name and design are based on the word 'bully', referring to their aggressive behavior, and a 'bull', referring to their horns and charging attack pattern.

Super Mario 64
In Super Mario 64, Bullies resembles a black sphere with green feet, angry eyes and two bright yellow bull horns. Bullies usually reside on platforms, occasionally in groups. To attack, Bullies charge themselves into their enemies in order to push them over ledges, knocking their enemies into lava or bottomless pits. The only way for Mario to beat a Bully is to push it into the lava. After being melted, a Coin will be tossed up to the platform that the creature was pushed off from. They are supposedly minions of the colossal Big Bully. They also appear in Bowser in the Fire Sea, the second Bowser boss level.

In Snowman's Land, a similar enemy known as a Chill Bully appears. It has a blue, round body, a single gold horn and green shoes, similar to a Big Bully.

Super Mario 64 DS
In Super Mario 64 DS, Bullies appear with the same role and behavior as before. In the remake, Yoshi, if used, must stomp them to push them back or use a cap, as his tongue has no effect on the Bullies. Bullies also appear in Chief Chilly's course in this game.

Super Mario 3D World
After an eight-year absence, Bullies reappear in Super Mario 3D World. However, their appearance has changed: they are now made of a blue shiny metal, their horns are golden and are bent forward with dark stripes at the base, and they appear larger than their previous incarnations. Also, they have rims just above their feet and red eyes. They no longer grunt, and make a metal sound when jumped on. They once again charge at the player, and can be knocked back by jumping on them, using projectiles like fireballs, or tapping them on the GamePad. Bullies will pause and teeter when pushed to the edge of a platform, giving the player time to land the final hit. If they are not knocked off, they will regain their balance and continue charging at the player.

Bullies can also be defeated by using the Lucky Cat Statue. A new boss, Prince Bully, also appears in this game.

Super Mario Maker 2
Bullies will be appearing in Super Mario Maker 2 as enemies that can be added to stages.

Mario & Luigi: Paper Jam
Bullies appear in Mario & Luigi: Paper Jam as an enemy, making this their first appearance in an RPG. They are only encountered at Mount Brrr and retain their physical appearance from Super Mario 3D World. Their main attack is ramming Mario, Luigi, or Paper Mario. Occasionally, bombs will appear behind the bros., and they must jump on the Bully while it is charging in order to not get pushed into the bombs. If Paper Mario jumps over the Bully while it is charging, it will run into the bombs, causing it to explode and take damage.

Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey
In Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, Bullies make an appearance in the Bowser Jr.'s Journey mode, where they are enemies and recruitable allies. Like in Mario & Luigi: Paper Jam, they use their Super Mario 3D World appearance.

Trivia

 * Models for Bullies are unused in Super Mario Galaxy. Similar to Super Mario 64 and Super Mario 64 DS, their bodies are made of a flat texture showing a picture of a black sphere, instead of a fully-modeled sphere.