Lego K-2SO (75120)

Lego K-2SO (75120)

This has a nice arm actuator, shown here from above.  If you push the button it compresses the hose that acts as a spring and moves the arms together but there’s enough play in the rest position to move the button from side-to-side which swings the arms together in an arc.

Lego K-2SO arm actuator