[@ramblingbard] No your post is great. Marceline is not the best roommate, and you show that perfectly. Marceline is like a sassy, sarcastic, ruthless, manipulative, cunning, and somewhat aggressive loud mouth. Saying shit to Ariel to test the boundaries, and see whats up would be something she would do. 

Like Kenzie from 'lost girl' mixed with Katherine from 'the Vampire Diaries', and some Rose from ' Vampire academy'.