Earless seals!!
Those glossy black eyes! The tiny hands! The roundness of their bodies... earless seals! They're so adorable you want to just poke 'em and hug 'em! You can see them at zoos and aquariums--usually laying around somewhere. They can submerge about 1,500 meters under water!
There has been surprisingly lots of illustrations of adorable seals uploaded to pixiv--check them out!