A: We always try to do things in Solo Fluxx in the same way as regular Fluxx – except when they have to be different. So Creepers do all the same things they usually do.

They prevent you from winning unless the Goal says otherwise or a rule or other conditions say they don’t matter. Sometimes you might need a Creeper to win, in which case you discard it as you do with the Keepers you win with. But if you have other Creepers that stop your win — even if the Goal is one that requires other Creepers — you must deal with those other win-stoppers before you can claim that Goal.