Spike Top

Spike Tops are Buzzy Beetles with shells that are red and have a single spike projecting out of the top (hence the name), making them impossible to be jumped upon, while still being resistant to fire, which makes them one of the most resilient enemies in the Mario series. Their defining trait is the adhesive quality of their feet, which allows them to crawl along vertical and upside-down surfaces. Despite being a shelled enemy, in the platforming games, any effective method of attack will defeat them instantly instead of having them retreat into their shells.

Super Mario World
Spike Top's debut appearance was in Super Mario World, where they would crawl around walls and ceilings of caves. They could only be destroyed by a Cape Feather, Shell, Starman, or by having Yoshi eat them. If Yoshi jumped on one, it wouldn't do anything to either Yoshi or the Spike Top. They are distinct from Buzzy Beetles in that their eyes are visible and their shells are flatter. Instead of having 4 legs like they do in all of their later appearances, in this game they have 6 legs.

Super Mario Advance 4: Super Mario Bros. 3
Spike Tops appear in the e-Reader levels of Super Mario Advance 4: Super Mario Bros. 3, a Game Boy Advance remake of Super Mario Bros. 3. In the game they attack just like they did in Super Mario World.

New Super Mario Bros.
They return once again in New Super Mario Bros., with the same attack pattern from Super Mario World. A Shell, Starman, or Mega Mushroom could defeat them, as could hitting a block one is on. They only appear in World 5-2, World 6-Tower 2, and World 8-Tower.

New Super Mario Bros. Wii
They also appear in New Super Mario Bros. Wii, mostly in World 2-3. They can be defeated by a Starman, Shell, hitting a block from below with the Spike Top on top of the block, or Ground Pounding the block with the Spike Top on the bottom. Additionally, Spike Tops can be frozen by ice balls, and used as weapons against other enemies.

Through hacking methods, it is also shown that Yoshi can completely eat Spike Tops, and safely jump on them (not affecting the Spike Top though) as well.

New Super Mario Bros. 2
Spike Tops reappear in New Super Mario Bros. 2, where they act the same as in previous games. They can be defeated with the same methods in the previous games and also by swinging Raccoon Mario's tail near them. They are incorrectly referred to as "Red Spike Buzzy" (their name in the Paper Mario series) in Prima's strategy guide due to their similar appearances.

New Super Mario Bros. U
Spike Tops Reappear in New Super Mario Bros. U. They behave exactly as in the previous games, and they may be eaten by any Baby Yoshi. However, they are invincible to Bubble Baby Yoshi bubbles.

Nintendo Adventures Books
A swarm of Spike Tops appear to attack Mario and Yoshi in Dinosaur Dilemma of the Nintendo Adventure Books, throwing themselves at the plumber and dinosaur as they are traveling through a desert. Depending on how the reader solves the accompanying puzzle, Yoshi will either eat all the Spike Tops, or one will succeed in knocking Mario out for several hours, allowing Bowser to easily conquer Dinosaur Island.

Paper Mario
In Paper Mario, Spike Tops appear as enemies in Mt. Lavalava. They are much more like Buzzy Beeltes in that they can be flipped over, are resistant to fire and explosion attacks, and attack by Shell Tossing.

Paper Mario: The Thousand-Year Door
In Paper Mario: The Thousand-Year Door, the Spike Tops have blue shells instead of red and also appear alongside Red Spike Buzzies, a sub-species of Buzzy Beetles that strongly resemble the Spike Tops' original appearance.

Super Paper Mario
Blue-shelled Spike Tops make a reappearance in Super Paper Mario. Due to this game being more of a 2D or 3D side-scrolling adventure and not a turn-based RPG they have the same attack patterns as in the regular installments of the Super Mario series.

Paper Mario: Sticker Star
Spike Tops reappear in Paper Mario: Sticker Star, this time having a red shell for the first time since the first game. Spike Tops appear in Rustle Burrow and Chomp Ruins. Once again, they cannot be stomped on unless using an Iron Jump sticker. They can retreat in their shells if Mario uses a Iron Jump sticker. Their only method of attack is going into their shell and ramming into Mario. Also, a sticker based on the Spike Tops' shell called the Spike Helmet can be used.

Super Princess Peach
In Super Princess Peach, it refers to Spike Tops as Mecha-Spike Tops. Despite this name, the Spike Tops of Super Princess Peach look no different than Spike Tops of other games, and therefore do not appear to be mechanical. Super Princess Peach also introduces an angry variety, the Mad Mecha-Spike Top, which can stretch out its spike to attack foes. They could only be defeated by using Rage or Poundbrella.