We analyze Dark Energy Spectroscopic Instrument (DESI) baryon acoustic oscillation, cosmic microwave background, and supernova data to explore the physical origin of the DESI indication for dynamical dark energy. Beyond the standard linear parametrization, $w(a)=w_0+(1-a)w_a$, we explore truncated alternatives and quintessence models. We conclude that there is compelling evidence for dark energy to be decaying in the late Universe, but the evidence for a phantom behavior, i.e., $w<-1$ at some redshift, is less significant. Models without phantom behavior are compatible with the data at the $2\sigma$ CL. Furthermore, we examine a concrete, theoretically well-motivated quintessence scenario with a Higgs-like potential, allowing for a direct comparison with parametrized approaches and testing its consistency with current observations. This framework enables a broader investigation of late-time cosmic evolution and reveals a 93.8% preference for a future transition into an anti–de Sitter space, which may ultimately lead to a cosmological collapse of our Universe.

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• Dark energy