Yes, it is very scary if you are not used to this kind of thing. If you go on, be prepared for absolute darkness. Also, they use the "4-D" effects, such as spraying water and tapping you on the shoulder, etc. The restraints are very tight; you can barely move. You will have a hard time holding the hand of your companion if you or they are scared. We took our nine year old sons on this ride at the beginning of a trip and almost ruined the whole trip for one of them. He is usually a brave kid - likes roller coasters, etc. - but he screamed the whole time at this attraction and then was scared to go on Haunted Mansion, ToT, etc.
Be prepared!
Have a good time on your trip!