The lifter of the lid gets a big surprise (3-6)
I believe the answer is:
eye-opener
'big surprise' is the definition.
(something eye-opening is very surprising)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for eye-opener that I've seen before include "This surprises greatly - makes you look" , "Surprise revelation" , "Startling thing" , "Fact that brings great surprise - wakes you up" , "Something startling" .)