For a jump scare, you want to check out Box of Fear by Andrew Melia
http://www.penguinmagic.com/p/1966, the Web by Jim Pace
http://www.penguinmagic.com/p/430, or the My Pet Boris phone app.
The basic effect here is that a spider appears on the back of a spectator's hand hen they least expect it.
A similar idea uses the Ominous deck by Diamond Jim Tyler. I have played with this and it never quite gets the reactions of the spider tricks above. The effect is that the deck turns into a dead spider or scorpion while in the spectator's hand.
http://www.penguinmagic.com/p/S22184
http://www.penguinmagic.com/p/S22185
If you are allowed to use fire at your haunted house 2 good fire tricks are Pyro Kinesis by Magic Smith
http://www.penguinmagic.com/p/9957 and Black Flame by Tom Phoenix
http://www.penguinmagic.com/p/9413
Pyro Kinesis is a sudden flame, where Black Flame is a nice reveal for a routine that is very creepy. Combined these two pieces could play well.
Look at Thread by Wayne houchin. It was once sold here on Theroy11 but is now available on Wayne's LIVE lecture. A similar effect is often achieved with a popcorn kernel and you can learn that approach by watching Amberlin and Ryan Stock's lecture:
http://www.penguinmagic.com/p/6661
http://www.penguinmagic.com/p/12239
These effects are way too uncomfortable for me. Spaghetti Al Dente by Chad Long is a little bit less gross but still good. You take a spagetti noodle, eat it and then regurgitate it whole. It's worth looking at:
http://www.penguinmagic.com/p/5467
Sick by Sean Fields is among the grossest possible magic tricks out there, coin to impossible location...lots and lots of blood. It's not the most practical thing in the world for walkaround.
http://www.penguinmagic.com/p/2249
Stigmata by Wayne Houchin and Banachek is good. The Shinkoh Twisting arm is great. My preferred handling is taught by Shimshi on his penguin Live lecture.