What is your favourite cover song?

I couldn't think of one for today's prompt, so I'm diving into the prompt archive today.

I think this one has to go to a cover of Bittersweet Symphony by Ren. He's done many great covers (all only available on his YouTube channel), but this is my favourite.

Ren doesn't just do covers the usual way, he adds his own unique lyrics and style to them as well, in his own spectacularly talented way.