We study the quantum and thermal fluctuations of eddy (Foucault) currents in thick metallic plates. A Casimir interaction between two plates arises from the coupling via quasi-static magnetic fields. As a function of distance, the relevant eddy current modes cross over from a quantum to a thermal regime. These modes alone reproduce previously discussed thermal anomalies of the electromagnetic Casimir interaction between good conductors. In particular, they provide a physical picture for the Casimir entropy whose nonzero value at zero temperature arises from a correlated, glassy state. Spatially diffusive transport is a basic physical phenomenon that has been studied with a wealth of methods. For example, the equation for heat conduction was solved by J. Fourier by his transformation that provided later the framework for quantum field theory. Remarkably, the Fourier modes of the diffusion equation itself,do not fit into a simple quantum field theory because they have purely imaginary frequencies. The quantization of (over)damped modes can be done, however, with an alternative approach, the 'system+bath' paradigm of dissipative quantum dynamics. In this picture, the observables relevant to a mode (specified, e.g., in Fourier space by its wavevector q) are damped in time because they strongly couple to a system with infinitely many degrees of freedom that are not directly accessible ('bath') [1]. The additional fluctuations the bath couples into the system, compensate at equilibrium for dissipative loss[2], even at zero temperature. This implies that a quantity like the zero-point energy of a damped mode is no longer given by the usual 1 2h ω q and must be redefined and reinterpreted. Indeed, the ground state of the combined system+bath is, in general, entangled : the corresponding interaction Hamiltonian is responsible for the change in the zero-point energy relative to the decoupled system [3,4]. Clearly this has an impact on all phenomena connected with fluctuation energy, for which the paradigmatic example is the Casimir effect [5].In this letter we discuss a specific example of 'diffusive modes': eddy (Foucault) currents in two metallic plates [6]. We address their quantum and thermal fluctuations and their role in the electromagnetic Casimir interaction [5]. Similar to the approach of Ref.[7], we isolate the contribution of eddy currents among all other modes. We show that these modes quantitatively reproduce the "unusual features" of the Casimir force between good conductors at finite temperature (as predicted by Lifshitz theory), that have been intensely debated for several years [8,9].To begin with, consider a metallic bulk described by a local dielectric function in Drude form:(Ω: plasma frequency, γ: damping rate). This system allows for a continuum of damped, chargeless modes with a (transverse) current density and (dominantly) magnetic fields at frequencies of order γ or below: they are called 'eddy' or 'Foucault currents' and are at the base of phenomena like magnetic braking or the familiar induction...