I liked using OOC red herrings to mess with players. Reading Ravenloft rules in 2nd edition was great to find some things to do to get players worried. It can work well in Rifts/BTS.
Have the characters get attacked by wolves. Write down 'lycanthropy' on your notepad and leave for a restroom break...nosey players will be squirming in their seats.
When a player gets hit for 1 point of damage detail the scratch minutely then as they sweat, tell them '1 point of damage'. They'll freak out wondering what else happened to them.
write down and fold up a paper on the character's dream from the previous night. make sure all the players see you hand it to the one.
In game I usually give 2-5 false clues, or clues that foreshadow things so far in advance the players think they are false until it actually comes to pass
I love being devious