Muggles' Guide to Harry Potter/Magic/Pygmy Puff

Overview
A Pygmy Puff is a miniature Puffskein.

Extended Description
Pygmy Puffs, as mentioned, are small Puffskeins, so share many of the same attributes, although Pygmy Puffs are either pink or purple, rather than the custard colored fluff of the Puffskein.

We are introduced to Pygmy Puffs in Harry Potter and the Half-Blood Prince when Ginny Weasley buys one from Weasleys' Wizard Wheezes. Ginny names her Pygmy Puff "Arnold", and is seen with it a few times in that year.

Despite their small role in the films and books, toy Pygmy Puffs can be purchased from the Warner Brothers online store and the "Wizarding World of Harry Potter" theme park.

Analysis
According to Fred and George, Pygmy Puffs are very popular among the younger witches.

We cannot speculate on why Ginny chose to name her Pygmy Puff as she did. We will note that the obvious namesake would be the actor Arnold Schwarzenegger, and we cannot see any similarity between the actor who portrayed The Terminator and a tiny purple mobile ball of fluff. Arnold is an anagram of Ronald, the full name of Ginny's next-older brother, but we also find it hard to believe Ginny would name a pet after him, even disguised.