The title of this article is official, but it comes from a non-English source. If an official name from an English source is found that is not from the English Super Mario Bros. Encyclopedia, the article should be moved to its appropriate title.
Usually, they will walk with their spikes retracted, and then stop to stick out their spikes as Mario approaches. Mario must wait before they retract their spikes again before he can jump on them. They can be defeated by a fireball, regardless of whether or not their spikes are protruding.