We investigate the dynamics of magnetic antivortices by time-resolved magnetic X-ray microscopy and high-frequency absorption spectroscopy. A method for the reliable generation of isolated magnetic antivortices is devised using specifically formed microstructures and two-dimensional sequences of magnetic fields. For antivortices the measured resonance frequency is lower than for comparable vortices. The deflection of antivortices by external fields reveals strong deviations from a harmonic potential as well as rather low annihilation fields. Spectroscopy yields a characteristic absorption signal for antivortices for strong excitation that indicates a continuous switching of the antivortex core.