  A detailed experimental and theoretical study has been performed about a
phenomenon, not previously reported in the literature, occurring in highly
viscous liquids: the formation of a definite pipe structure induced by the
passage of a heavy body, this structure lasting for quite a long time. A very
rich phenomenology (including mechanical, optical and structural effects)
associated with the formation of the pipe has been observed in different
liquids. Actually, the peculiar dynamical evolution of that structure does not
appear as a trivial manifestation of standard relaxation or spurious effects.
In particular we have revealed different time scales during the evolution of
the pipe and a non-monotonous decreasing of the persistence time with
decreasing viscosity (with the appearance of at least two different maxima). A
microscopic model consistent with the experimental data, where the pipe behaves
as a cylindrical dielectric shell, has been proposed. The general time
evolution of the structure has been described in terms of a simple
thermodynamical model, predicting several peculiarities effectively observed.
