100 Words is one of meme's common threads.
Despite the title, fills in 100 threads do not have to be drabbles of exactly 100 words; they're generally interpreted as “at least 100 words of the prompt”.
The first such thread was Write 100 Words of Hairbrushing in March 2017.
Past 100 words threads (including those with no fills) are listed here, and 100 words fills are here.