Danny Hylton's brace helped Aldershot to a win as Shrewsbury slipped out of the League Two promotion places.
Jermaine McGlashan found Hylton in space on the left and the striker lashed home from just inside the area.
Ben Herd, formerly of the Shrews, scored his first goal for the Shots with a hugely deflected effort.
After Mat Sadler brought down the troublesome McGlashan in the penalty area late on, Hylton was left to round off the win with a well-struck penalty.
The Shrews fell two points behind Bury into fourth place, while Aldershot leap-frog Crewe into 12th.
Shrewsbury manager Graham Turner told BBC Radio Shropshire:
"Our record in bouncing back after a goal down is normally good, and we just didn't see that result coming.
"We had some good early possesson, but our carelessness on the ball contributed to us not making any real chances.
"It was a bit flat, but we weren't in any sort of difficulties until they scored - it was the first shot of the game.
"Second half we had a couple of good chances, especially Matt Harrold heading over from close range, and had that gone in we might have got something but we lost the momentum after that."