Are there any ancient greek gods or goddesses that can shape-shift?
Just about all the gods changed their form every now and then. Like Zeus, he became a bull, a shower of gold, a swan, a peacock and more; and all for the purpose of pursing different women he was interested in at the time. (Because nothing is more seductive than a shower of gold!) There is also a story in which Zeus and Hermes, out of sheer boredom, disguised themselves as peasants to see how the people would treat them. Unfortunately for the people, Zeus and Hermes didn’t get a satisfactory reception. If you want to, you can read more on Zeus here: http://www.theoi.com/Olympios/Zeus.html Apollo once took the disguise as an old woman in order to seduce Khione. (Ok, I’d say a shower of gold is much more seductive…) His brother Hermes had already had his fun with her…but anyway you can check out the story here: http://www.theoi.com/Olympi
