Confinement in non-Abelian gauge theories is commonly ascribed to percolation of magnetic monopoles, or strings in the vacuum. At the deconfinement phase transition the condensed magnetic degrees of freedom are released into gluon plasma as thermal magnetic monopoles. We point out that within the percolation picture lattice simulations can be used to estimate the monopole content of the gluon plasma. We show that right above the critical temperature the monopole density remains a constant function of temperature, as for a liquid, and then grows, like for a gas.PACS numbers: 12.38. Mh, 25.75.Nq, 11.15.Ha, 12.38.Aw It is well known, the properties of the Yang-Mills plasma turned out to be unexpected. In very brief, the plasma is similar rather to an ideal liquid than to a gluon gas interacting perturbatively [1]. Amusingly enough, many features of the plasma find their theoretical explanation in terms of a dual, or string formulation of YangMills theories [2] which has been derived only in the limit of infinite number of colors and supersymmetry.It is a challenge to uncover dynamical picture behind the observations on plasma. In particular, equation of state has been studied in detail through lattice simulations both in case of SU (2) and SU (3) gauge theories [3]. It turns out that global characteristics of plasma are not in contradiction either with perturbation theory or with the string picture, or with quasiparticle models [4], and do not provide much insight into the plasma dynamics.Infrared-sensitive variables could be more helpful to identify specific degrees of freedom of the plasma. An example of such a variable is the viscosity which turns to be very low [5]. Other examples are the string tensions σ andσ of the spatial Wilson and 't Hooft loops,respectively. Here A is the area of a minimal surface spanned on the corresponding contour. Thus, we come to consider light degrees of freedom of the plasma. On the theoretical side, our guiding observation is that degrees of freedom condensed at T = 0 form a light component of the thermal plasma at T > T c . Since the confinement of color in non-Abelian theories is due to magnetic degrees of freedom [6,7,8] the magnetic component is to be present in the plasma as well.In the string picture one postulates existence of electric strings which can be open on external quarks (Wilson line) and of magnetic strings which can be open on external monopoles ('t Hooft line). At T = 0, the electric strings have a non-zero tension, measured through the Wilson line. One of the earliest proposals for the mechanisms of deconfinement is percolation of electric strings [9]. Generically, percolation means that there is large (potential) energy E and large entropy S which cancel each other. Thus, within this mechanism it is long strings which become tensionless and percolate. Lattice data [10] provides evidence for large entropy S = −(∂F/∂T ) V of the electric strings, since the average of the Wilson line W ∼ exp(−F/T ) can directly be related to free energy F = E − T S. The poten...