I give you the barbell paused squat. One of the most under utilized yet greatest leg exercises of all time. There is a right way to do these and a wrong way. The wrong way makes them even easier than a regular squat. Form here is very important. The idea is to increase difficult and muscle engagement.
The right way:
-Slow controlled movements
-The pause is once your legs hit 90 degrees with your hamstrings and quads parallel to the floor.
-Do not pause any lower as that greatly decreases the difficulty
-DO NOT PAUSE LOWER THAN PARALLEL
-Maintain tightness in your entire body and squeeze your core as you pause. Do not lose form just because you are pausing. All other form tips for squatting still apply.
-Keep feet firmly planted. You should feel very balanced during your pause. Drop the weight until you have complete control.