Super Mario 64/Characters

Throughout the game, Mario will encounter various characters which may damage his health to various severities, but can also have utilities.

Goomba
Gives Mario one unit of damage when bumped, and one yellow coin when stomped.

In Tiny-Huge-Island, they appear as tiny and huge variants respectively, where the tiny causes no damage and disappears without coin when bumped, and one yellow coin when stomped. The huge causes two units of damage when bumped, and one blue coin when stomped. The sound when stumping noticably differs from ordinary goombas.

Bob-omb
Causes no damage when touched, but two units of damage when exploding. Can be picked up and thrown.

Pink Bob-omb
They do not explode. Pressing "B" near them causes them to unlock a cannon. An additional one in Bob-omb battlefield tells a story about rivalry with the normal (grey) Bob-ombs.

Koopa
Causes no damage when bumped, gives a blue coin (worth five coins) and a Koopa shell when stomped. The shell can be used to surf on water and lava, and allows riding up slippery slopes uphill.

A stompable Koopa is found in Bob-omb Battlefield. In some courses, such as Jolly-Roger Bay and Shifting Sand Land, Koopa shells are located in breakable boxes.

Owl
Elevates Marios altitude and provides a birds-eye view of the course. Found in Tall Tall Mountain, Whomp's Fortress, and Snowman's Land.

Fly-guy
Spits fire, which causes three units of damage. Bumping causes two units of damage. Stomping causes Mario to spin, which allows him to glide for long distances through the air. Found in Tall Tall Mountain and Snowman's Land.

Thwomp
Quader brick which tries to throws itself on Mario. Causes three units of damage if it flattens Mario. Needs to be stomped using ground pound. Found in Thromp's Fortress and Bowser in the Sky.

Chuckya
Grabs and throws Mario. Dangerous because located near tall slopes and high platforms such as in Rainbow Ride, Wet-Dry World, Bowser in the Sky, and Tall-Tall Mountain. Can be destroyed by being picked up and thrown by Mario.

Toad
Located throughout the castle. Engaging by pressing "A" makes them tell a story and/or praise Mario. Three of them provide a star, one located in the basement near the entry to "Hazy Maze Cave", one in the upper hallway, and another one in the dark_cyan-walled star room near the top of the castle.