  Linear temperature dependence of transport coefficients in metals is
habitually ascribed to non-Fermi-liquid physics. Here we establish the T-linear
behavior for 2D electron fluids, systems in which carrier collisions assist
conduction, leading to resistance decreasing with temperature. This behavior
originates from exotic hydrodynamics described by Fermi surface modulations
evolving in space and time in an amoeba-like loop manner that features a large
family of long-lived excitations manifest as multiple viscous modes. A cascade
of these modes results in a linear T dependence that extends down to lowest
temperatures, as well as a Kolmogorov-like fractional power -5/3 scaling of
conductivity vs. wavenumber. These dependences provide a smoking gun for
nonclassical hydrodynamics and are expected to be generic for
strongly-correlated 2D systems with simple near-circular Fermi surfaces.
