The Twelfth Doctor

If you cast the spell and choose not to copy it, no opponent will get to copy it either.

Neither "Time" nor "Lord" are creature types. Some older cards were printed with the subtype "Lord," but all of those cards have updated Oracle card text that removed that type.

If any additional or alternative costs were paid to cast the spell with demonstrate, the copies will see those choices as well. For example, if the spell has a kicker ability and was kicked, the copies will also be kicked.

If the spell had an X value chosen for it as it was cast, the copies will have the same value of X.

If you copy a spell with demonstrate, you then immediately choose an opponent. If they copy the spell, it goes on top of the stack.

If an effect instructs you to choose a creature type, you may choose Time Lord.

Unlike other creature types in Magic that are each only one word, the two words "Time Lord" represent a single creature subtype. Time Lord is the only two-word creature type.

If the spell with demonstrate had any modes chosen for it as it was cast, the copies will have the same modes chosen for it.