Busch Gardens -- Pregnant Woman Sues Over Chainsaw Horror

Halloween at Busch Gardens became a real-life nightmare for a pregnant woman who claims she was mowed down by other terrified patrons ... after chainsaw-wielding actors created a panic in the park.

Brittany Lipscomb claims she was at the Williamsburg, VA theme park 2 years ago -- for a ghoul's night out -- and was being extra careful for her safety since she was pregnant.

In her lawsuit -- obtained by TMZ -- Lipscomb says the park hired costumed characters to chase people around with chainsaws ... causing them to run recklessly through the park.

Lipscomb claims she was knocked to the ground by the stampede ... suffering serious injuries -- including emotional distress for the well being of her unborn child. She never says if the kid was actually hurt ... but now she's suing for $25K.