scratch (your) head

to have difficulty understanding something.

A lot of people must be scratching their heads and trying to figure out what happened.

• play someone at their own game
• play someone for a fool
• play someone for a sucker
• play something by ear
• play the field
• play the fool
• play the game
• play the goat
• play the market
• play the waiting game
• play to the gallery
• play up
• play up something
• play up to
• play up to someone
• play up to something
• play with
• play with fire
• play with something
• play your ace
• play your cards close to chest
• play your cards close to your chest
• play your cards right
• play your part
• plot thickens