my first post :3 tell me your favorite marine creatures!!

i'm getting interested in the sea and want to use my free time to research some marine animals and their relationships with other animals, i was kind of doubting about where to start cuz there are lots of creatures on the sea and i know the ones that are common knowledge but i wanted do indulge more on other animals hehe (⁠ꏿ⁠﹏⁠ꏿ⁠;⁠) if someone is into this topic and can recommend me some books or just tell me some animals i would appreciate it a lot!! thxx