One of the scariest rides at Knott's Berry Farm is the Boomerang roller coaster. While nothing new, this feared amusement ride pulls riders backwards up a tower and then drop them 12 stories through three twisted loops. You then climb the opposite end, another tower forwards and again are dropped, but this time going backwards to repeat the three loops. The Boomerang is considered an extreme roller coaster.
Boomerang photo courtesy of Ultimate Rollercoaster.