Saying as a command, "Be creative!"
Could I say, "Sé creativo"?
This sounds incorrect to me.
4 Answers
For what it is worth, some people think you can say it that way:


Sé creativo (tú)
Sed creativos (vosotros)
Sea creativo (usted)
Sean creativos (ustedes)
I agree with Bosque.
A different way of saying it would be to specify what is to be done in a cerative manner:
Example: ¡Hazte un selfie creativo!
Love those pictures. Thanks!