I think where you go with this sentence is dependent upon a number of things:
-what is the purpose and tone of your piece? Is it ominous? Is it sad? Is it injected with humor (dark though that might be)? You want to find a similie that reflects the tone of the piece and brings the reader closer to whatever your purpose is
-I love the idea of just listing as many things as you can think of and then finding what strikes you. I would even say combine that suggestion with the one above about keep writing and then come back. Write a list right now, then leave it alone and keep writing. Then come back to your sentence and your list and see what comes up out of your brain
-Think about what you think the smell actually smells like and then go one of two ways: use a similie that reflects that smell or use a similie that is completely the opposite. I love the juxtaposition of different ideas in creative writing.
-I love #3's idea about the dead crab smell. It cracks me up!
I agree with #4 in that you should explore a variety of ideas. Listing lots of suggestions and then selecting the one which fits best may work. Often in this sort of situation I continue with the writing then go back
to create an image which fits with the description as a whole.
I would go with something less concrete - 'clung like an oppressive memory' or 'hung like a dejected overcoat".
I suggest you come up with a variety of endings and then choose one. Get really goofy. You could say "like slime on a week-old hamburger" or "like a bad date". Keep adding ideas until you find one that really seems brilliant. That's your answer. Don’t try to think, just write.
Perhaps its the verb that's catching you up. Changing the verb from "clung" to "filled" or "dominated" may bring some new ideas and images to mind.
I'd like the house to smell like dead crabs, but maybe that's a bit too obvious of a direct verbal metaphor.
How about this creative sentence: The foul stench clung to the house like the last drop of ketchup in the bottle. A simile is a comparison of two unlike things, so comparing the smell to the condiment of ketchup might be an interesting mixture of tastes and smells. While not too obsessively synesthestic, it might make for an interesting comparison in your class assignment or whatever you are writing.