Examples:

• The injured deer was a sitting duck for the hungry predators in the forest.
• The company's outdated cybersecurity system made them a sitting duck for hackers.
• The stranded hiker was a sitting duck for the approaching storm, with no shelter or protection.
• The slow-moving car was a sitting duck for the impatient drivers behind it.
• The unarmed soldiers were a sitting duck for the enemy attack, with no weapons or reinforcements.
• The injured player on the field was a sitting duck for the opposing team, with no way to defend themselves.
• The small fishing boat was a sitting duck for the approaching storm, with no means of escape or shelter.
• The unprepared tourist was a sitting duck for the pickpockets in the crowded market.
• The isolated farmhouse was a sitting duck for the burglars, with no neighbors or security system.
• The malfunctioning vehicle was a sitting duck for the tow truck driver, with no way to fix itself on the side of the road.
• When my car broke down in a bad neighborhood, I felt like a sitting duck, just waiting to get robbed.
• The shop where Ishigaki is a sitting duck.
• The guy's a sitting duck.
• I feel like a sitting duck out there.
• Goliath is a sitting duck.