Hey, everyone else was doing it

A malamanteau is a word which is both a portmanteau and a malapropism. This means that the word must

• (portmanteau) be a combination of two (or more) other words (and their meanings), and
• (malapropism) have been used because it sounds correct in that place in the sentence, but is actually either nonsensical or an unusual word.
  

"Malamanteau" also implies that the speaker or writer has used language in an unusual way.

The word was first published on the Internet here. The examples by which the word was defined are

During the first discussion, the guy described his misunderstanding of what someone was saying by stating, "I misconscrewed it up."

The second time, another guy explained his inability to talk while upset by saying he was, "flustrated."

In a curious twist, "malamanteau" is a portmanteau of "malapropism" and "portmanteau".

As a result of a recent xkcd comic, "malamanteau" is now also a neologism ("a newly coined word that may be in the process of entering common use, but has not yet been accepted into mainstream language").