  This paper is devoted to some simple approach based on general physics tools
to describe the physical properties of a hypothetical particle which can be the
source of dark energy in the Universe known as phantom. Phantom is
characterized by the fact that it possesses negative momentum and kinetic
energy and that it gives large negative pressure which acts as antigravity. We
consider phantom harmonic oscillator in comparison to a standard harmonic
oscillator. By using the first law of thermodynamics we explain why the energy
density of the Universe grows when it is filled with phantom. We also show how
the collision of phantom with a standard particle leads to exploration of
energy from the former by the latter (i.e. from phantom to the standard) if
their masses are different. The most striking of our conclusions is that the
collision of phantom and standard particles of the same masses is impossible
unless both of them are at rest and suddenly start moving with the opposite
velocities and kinetic energies. This effect is a classic analogue of a quantum
mechanical particle pair creation in a strong electric field or in physical
vacuum.
