I missed most of the episode! DX but what I do know is that Greg can't fuse with Rose back when she was around! I felt really bad for Greg because Pearl kept on downsizing him and lied to him saying she doesn't care about him because he's just a human. I believe Pearl was jealous of Greg back then and wanted him to stay away from her beloved Rose. Yet I still think Pearl's still jealous of Greg and Steven as well. Think of it as a love triangle in a way.



I imagine that one day, Pearl will get too angry and upset with losing Rose to the point she'll try to kill Greg which will lead Steven to fight Pearl in order to calm her down and save is father from certain doom.