Possible Clues:

• Planetary threat in some sci-fi films
• Body in a shower?
• You need space for anything sounding fatter than this
• Space traveler
• Sounds as if there's more flesh on a visitor from far away
• Become a visitor with more flesh on, by the sound of it
• The space traveller's remote after being set off
• Thing from space that sometimes hits Earth
• That sounds comparatively beefy from out of this world
• A fireball from remote parts