Board Thread:General Discussion/@comment-24863788-20141216060128/@comment-24720945-20141217150344

It's probably that Ursula was still a sea witch in Heroes And Villains, but later became a goddness in Ariel, because in Skin Deep, when Regina mentioned Ariel to Rumple, Belle had already been banished, which means the flashbacks in Heroes And Villains took place before the flashbacks in Ariel. Plus, mermaids can swim through worlds, so I bet Ursula can do that as well.