How do you explain the concept of “dreams” to a 2.5 year old?

One of Caitlin’s fave TV shows, Bear in the Big Blue House, had an episode where Ojo had planned a sleepover with her friends.

Halfway through the show, Ojo awoke with a nightmare, where she dreamt of monsters. Caitlin asked what was wrong with Ojo that made her cry & needing comforting from Bear.

How do you explain the concept of dreams, whilst skirting around the other concept of monsters, to a 2.5 year old?

“my point of view”

“these shoes are made for walking…”