"10 Colorful Idioms: out of blue for your gray matter [infographic]"
idiomland: “ “Bend over backwards” means “to try very hard to do something”. Example: I keep bending over backwards to lose weight, and I’ve only lost five pounds! Get our apps for learning English: learzing.com ”
“Set upon” means “to attack violently”. Example: The dog set upon the postman and chased him up a tree.