Answer:
A darkΒ-colored creature serenaded by Lennon and McCartney.
Dark, feathery, and popular in Baltimore and fantasy books.
I have a shell and live in the sea. I move slowly and can hide in my shell. What am I?
Stealthy as a shadow in the dead of night, cunning but affectionate if given a bite. Never owned but often loved. At my sport considered cruel, but that's because you never know me at all.
I am a animal that is cute but dangerous, what am I?
I hold two meanings. With one I may be broken, with the other I hold on. What am I?