While I can't find it right now,I do remember that in UF the Master Chief is Salusian and therefor has the ears on the top of his helmet. And in case anyone didn't know in Halo Infinite, you can now buy cat ears for your spartan armor. Picture below, please let me know if I didn't do it right.
I won't fight you Atton. I don't care, I just want you to die. (Disciple and Atton KOTOR2)