p-branes. A point particle can be viewed as a brane of dimension zero, while a string can be viewed as a brane of dimension one.
They probably don't look anything like this but this is how I imagined them the first time I read one of Stephen Hawking's attempts to make string theory, m-theory and supergravity more accessible to the rest of us.
I hope that his consciousness somehow found answers to these questions as he transition to the other side of the mortal veil.
Thank you, Dr. Hawking.