Tentacles. Lots of tentacles.
Or, in other words, there's always the threat of aberrant or Far Realmsian incursions in my games. Hideous things that defy time and space are usually par for the course. I've also discovered the joys of shadowy manipulator villans, and all of my more recent games have had powerful beings toying with the players, sometimes known, sometimes not (rakshasas, illithids, yugoloths, that sort of thing).
Demiurge out.