CupcakKe was supposed ... joined Charli XCX on stage at music festival Lollapalooza, dancing her way across the stage as she belted out her viral hit CPR about foreplay performed with life-saving ...

Watch as the Chicago-based rapper and performance artist CupcakKe is not only seriously on her game here as an MC, but shows up dressed up in a homemade duck suit while firing off lyrics like ...