I will answer this assuming we are referring to Disneyland Resort which includes both Disneyland and Disney's California Adventure.
Assigning a score of "scariness" to a ride/attraction can be an imperfect science as there are several factors that play into what makes one of these experiences scary.
Darkness: Rides that take place in the dark tend to be percieved as scarier than those in the light.
Speed: Rides with greater speed or even percieved greater speed tend to be identified as scarier rides.
Imagery: Gruesome or frightening imagery intensifies the fear factor
Ride History: Past events that have resulted in injury or death on a ride can certainly increase one's fear of a ride.
Heights: Rides that involve great heights can be scary as we people tend to not enjoy falling very much.
Audio: Loud, intense soundtracks or sound effects cause a ride to seem more frightening than it really is.
Considering those factors we can safely say the following:
- California Screaming is the fastest ride in the parks and it involves several climbs to fairly great heights. If speed and heights make you nervous this will likely be a very scary ride for you. I find it just to be fun and intense...not scary in the slightest.
- Big Thunder Mountain Railroad has dark moments and has claimed a life and caused several injuries during an accidental derailment several years back. This black eye in it's history makes it a little more scary to me personally but the fantastic themeing make up for it and as a result, this train ride/ roller coaster isnt' really too bad at all.
- Indiana Jones has some gruesome and frightening imagery in the dark as well as a loud soundtrack. While it might frighten a rider the first time around, I think all subsequent rides will not be scary in the least.
- Space Mountain has a loud soundtrack, a dark enviornment, and a percieved high speed. You are really going only 25ish mph but it feels more like 80. To me this is personally the most frightening ride at DL or DCA. Because one can't see where the turns are and because the speed feels so great I often find myself thinking that a potential crash is just about to happen. This one gets my vote.
-Tower of Terror- Loud soundtrack, dark environment, spooky images, and several drops can ratchet up the fright factor on this one. I personally don't find it frightening but I dislike the drop sequence. I always feel a little sick afterward.
i would say space mountain is good but not very scary.
[for me] but i would recommend rock en rollacosta . for me the scariest ride is California screamin but that is in California adventures i love space mountain
Many people say that the Medusa is the scariest ride.
Saw-the ride at Thorpe park, England is the scariest ride in the world.
dolly parton
Talon
Intimidator
The worlds scariest ride is the spinning teacups
Oblivion
The Jolly Rocker
Superstar Limo is the dumbest stupidest lamest ride in the history of disneyland
bungee or tornado
the aqua loop :)
super man ecape