  From the microscopic point of view, realistic black holes are time-dependent
and the teleological concept of event horizon fails. At present, the apparent
or the trapping horizon seem its best replacements in various areas of black
hole physics. We discuss the known phenomenology of apparent and trapping
horizons for analytical solutions of General Relativity and alternative
theories of gravity. These specific examples (we focus on spherically symmetric
inhomogeneities in a background cosmological spacetime) may be useful as toy
models for research on various aspects of black hole physics.
