Big Shot on the Stratosphere is scary. It makes a horrible clunk as you reach the top, very unnerving!
Although the scariest of the three rides on top of the stratosphere is the see saw one. You hang quite well off the edge of the tower, and about the third time, you feel like you're actually dropping after it's stopped, because it goes further down on that time. I screamed quite a bit. :P
The other one's a bit crap, TBH - the thrill's over before the ride starts to spin.
Adjective: Fat, round, or bulging.