I'm blocking on an image of a Hawaiian market. Rather than struggle I'm changing lanes to another idea, Zalien the Alien.
Zalien interrupts three trick-or-treaters on Halloween night and samples some of their chocolate. Then he remembers that for aliens, chocolate upsets their multiple tummies. Adventure ensues.
I have the characters but I need a good space ship. Here I scribbled some ideas.
Try it, it's fun. Each scribble should take a minute or less: