Goomba

The Goomba is the first enemy to ever appear in the Super Mario Bros. video game for the NES.

They are one of the most common enemies to appear in the series, along with Koopa Troopas and Shy Guys. They are usually small, brown and walk sideways, with no specific objective to speak of. Goombas usually harm Mario by bumping into him, but they've sometimes been known to bite, headbutt or jump on Mario in order to harm him, especially in the Mario RPG series.

Variations of Goombas
There are many variations of Goombas that appear throughout the series, each having even the most minor separation from a regular Goomba, ranging from strength to color to abilities.

A common variant is the Paragoomba, a Goomba with white, feathery wings that allow it to fly. Some Paragoombas are only capable of fluttering into the air, while others are capable of flying freely.

The Spiked Goomba is a Goomba with a spike on top of its head. They appear in both Paper Mario games. If Mario jumps on them, the spike will hurt him, so he must hit them with his hammer to damage them.

The Goomba Bros. are a Red Goomba and Blue Goomba who appeared in Paper Mario. They are bigger and more powerful than the regular Goomba. They will appear again in Super Princess Peach for the Nintendo DS.

Tanoombas only appeared in Mario & Luigi: Superstar Saga, where they were commonly found near the BeanBean Kingdom. They share the regular traits of the Goomba, but are covered in Tanuki fur, a Tanuki tail, and a Tanuki leaf. In battle, they are able to jump high into the air, and suspend themselves in the air temporarily by either swinging their tail or spinning around, using their tail as a weapon to attack enemies. The Tanuki leaf on the top of their head allows them to transform into Mario or Luigi, but will still feature the Tanuki tail. It is not yet known whether or not Tanoombas will appear in the Nintendo DS game Mario & Luigi: Partners in Time.