There are thrilling rides and there are scary rides and there are almost unbearbale rides. And then there is the Loch Ness Monster, which emerges officially this weekend at the Busch Gardens Williamsburg theme park.

Monster is the name for it. It is, they claim, the tallest, steepest, fastest and most convoluted roller coaster in the world. No coaster connoisseur will be able to hold up his head until he has ridden it. Then the problem becomes how to hold down lunch.

How wild is it? Well, it starts out with a long, slow, 13-story climb, during which the victim is likely to find himself reviewing his life and resolving to do better, if given another chance.

Then the 24-passenger car drops 114.2 feet, reaching nearly 70 mph. If it dropped 117.2 feet, it would land in a river. They say the angle is 55 degrees, but it looks and feels vertical; the passengers are in free-fall, held in by an over-the-head padded bar, which until that moment seemed a little excessive.

Ridders, assuming their eyes are open, find themselves staring into the upturned faces of people on the riverfront promenade. The expressions are the same ones you see on bystanders at a gory traffic accident.

The pullout is 3.5 Gs, which leaves your larynx where your liver used to be, and momentum carries the car back up 91 feet, around a 90-degree curve and down a 57-foot drop that runs out immediately in a 360-degree loop. The entry speed into the 30-foot loop is 43 mph; by the time your are fully upside down - 80 feet in the air - the speed has dropped to 23 mph. While they were testing the Monster a sandbag fell out of the lead car at the top of the loop and landed in the last car.

"All the engineers, park employees and other sucker we sent out on test rides came back, though," said Busch publicist John Hunter. "We had a guy keep count."

After the first loop the car plunges into an artificial mountain where it does three tight, descending circles in total darkness, taking what seems like hours.

After emerging into the light, the car grinds up a 75-foot incline, giving the passenger more time than they want to contemplate the second loop, which interlocks with the first and, if all goes right, puts you almost head-to-head with the fools going through it.

The ride ends with a jolt of brakes that catches your stomach halfway back down from your throat. There is a squad of nice, strong young women who are trained to heave survivors out of the cars.

How bad is it? Well, they put a recorder in one car during a test run and it came back with nothing on the tape but the roar of the wheels and the rush of the wind. We had not been able to scream.

It takes about a dozen rides to fully appreciate the Monster, the first few trips being devoted to trying to keep your eyes open. The thing is marvel of engineering (by the Arrow Development Co. of Mountain. View, Cal.) and a masterpiece of construction by what must be the most skillful team of high-iron men in the world. The $5 million it cost could be justified on aesthetics alone, and it's almost as much fun to watch as to ride.

The trip takes 2 minutes 20 seconds ove 3,240 feet of track and is unique among roller coasters in that it doesn't seem too short. The Monster can handle up to 2,000 idiots per hour.