In Star Wars: A New Hope, when Luke finds R2-D2 (who runs away to find Obi-Wan), it says something that C-3PO translates. Here is the conversation.
Luke: What's wrong with him?
C-3PO: There are several creatures approaching from the southeast.
Luke: Sand People. Or worse!
So, which worse thing was he expecting here? It should be something that is worse than Sand People, but what was it?