To write a story that you make up out of your head.
No. The idea that prose is inferior to verse is laughably old fashioned - and has always been nonsense, just like the attitude that poetry is 'soppy' and sentimental.
There is plenty of outstanding creative writing in prose - novels, short stories, literary essays, autobiographies and accounts of travels. The key to creative writing is the use of language, not usually a riotous imagination.