Dried Cow Fetus is a meme apparently created and first introduced by the reddit user /u/ClamCrackingClown. The first ever mention of the meme was in this comment by the user.

Whereas the original Dried Cow Fetus image was first posted in this thread.

(Image link)

The meme received mild recognition shortly after its creation, gaining a measly 39 upvotes on the reddit debut of the cow fetus image.

/u/ClamCrackingClown mentions the Dried Cow Fetus several times, one of the most notable being here.

The meme was not always well received in its early days.

The Dried Cow Fetus meme has appeared on 4chan.org multiple times:

DCF on 4chan

The original Dried Cow Fetus edited with a Pepe head.

Another appearance on 4chan

Though the original creator of the meme appears to be inactive on reddit (he/she recently published another Dried Cow Fetus image on imgur), other users have tried to keep the meme alive, sometimes in very relevant places.

Starting on July 12, 2015, a new image began circulating on 4chan alluding to the creation of the Dried Cow Fetus. This image features Pepe the depressed anxiety toad, who is a major sensation on 4chan.