The gemerah discusses two commonly worshiped images, the nursing mother and Sar Apis.
The gemarah identified the former with Eve, who "suckled the whole world" and thus became a deity. The latter is said to represent Joseph who was a sar prince who calmed the world by handing out grain.
I hate to be a party pooper, but even a non-specialist like me thinks Seraphis and Isis, who is often depicted nursing a child, are better fits for this description. Though the gemarah's guesses are charming, I'm not sure what to make of them. Seraphis was an Egyptian deity originally, who developed into a Greek and then a Roman god. If it possible he was first based on Joseph? Even the grain measure Sar Apis is said to carry fits the description of Seraphis, but then Joseph did make his name in Egypt by handing out grain. Mysterious.
UPDATE: Art Scroll pays lip service to the possibility that Sar Apis is Seraphis; nothing about Isis though. Rashi is silent, too. Haven't checked others.
Related daf posts from Avoda Zara.
Search for more information about [topic] at 4torah.com.