To have such a series of thoughts; to woolgather.
A spontaneous series of thoughts while awake not connected to immediate reality.
to use one's imagination
To form a mental image of something; to envision or create something in one's mind.
to assume
To believe in something created by one's own mind.
to conjecture or guess
Used to mock some idea.
A short fanfic or prompt placing a reader insert in a novel scenario with a character or celebrity.