It only looks bad if you are dishonest, seem desperate, or haven't put in effort.
It's perfectly fine to contact multiple professors in separate emails where each is somewhat customized, especially in a field where students are admitted to a program rather than a specific lab directly. You are on a mission to gather and share information, you aren't promising yourself to each of them.
Your goal in graduate admissions should be to find a good fit between you and a professor.
If you are not actually interested in both lions and cuttlefish, you should not email the lion professor and tell her how much you like lions and your passion is to be out on the African savanna (and by implication, could never study cuttlefish), and then do the opposite with the cuttlefish professor. Do consider that professors may talk to each other, so if you think your email to one professor would be embarrassing if another professor saw it because it differed so much to the one he read you should rethink a bit.
Having seen these sorts of emails from prospective students, I would dial back the flourishing prose about fascination: unless you have a history of work in a specific area it can come off as a bit superficial or naive, and maybe a bit desperate. Instead, be honest and reflective both with yourself and in your emails: grad school is a big commitment, don't commit to something you can't actually find some interest in. You don't need to convince someone that studies cuttlefish that cuttlefish are awesome - they know it better than anyone else. Convince them that you are ready and able to learn, pick up some of their papers to show you've done your homework. "I'm interested in your work about lion manes in mate attraction" is a lot better than "Lions are the best mammals ever I've really been fascinated by them since I was young": it shows you know and read about what the lab does (they study mate attraction in lions).