When something happens suddenly and unexpectedly, it can be described in different ways, especially when using synonyms for "appear abruptly." For instance, it can be said that things "emerge suddenly," "surface instantly," or "manifest abruptly." Other synonyms for this phrase may include "pop up suddenly," "leap out quickly," or "explode onto the scene." It can also be described as appearing "unexpectedly," "startlingly," or "abruptly." Other expressions that convey this meaning include "out of nowhere," "all of a sudden," "instantaneously," and "like a flash." Ultimately, there are many ways to describe an abrupt appearance, and using interesting synonyms can make your writing more engaging.