dream up

US /ˌdriːm ˈʌp/
UK /ˌdriːm ˈʌp/
"dream up" picture
1.

idear, inventar, imaginar

to invent something in your mind, especially something unusual or impractical

:
He dreamed up a crazy plan to travel around the world in a hot air balloon.
Él ideó un plan descabellado para viajar alrededor del mundo en un globo aerostático.
Where did you dream up that ridiculous idea?
¿De dónde sacaste esa idea ridícula?