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 dominant negative pressure which acts as antigravity. We
consider a 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
extraction 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 mass is impossible unless both of them are at rest and suddenly start
moving with opposite velocit…