  Magnetic skyrmions, a topologically stable spin swirling object, have
attracted a great interest due to their potential applications in future
spintronics and ultra high dense magnetic memory devices. Cu$_2$OSeO$_3$ is
only known insulating chiral helimagnet with multiple phases including skyrmion
phase. Existence of skyrmion phase as well as first and second order phase
transitions make Cu$_2$OSeO$_3$ a promissing candidate for investigating
complex magnetic phenomena. Here, we report that both first and second order
magnetic phase transitions are responsible in determining the phase diagram
with atleast two multicritical point in Cu$_2$OSeO$_3$. Fluctuation-induced
first order transition is realized as a precursor for skyrmion phase over a
small window of temperature of magnetic field. The evolution of field dependent
entropy at the phase transition provides the evidence for tricritical point.
Furthermore, existence of commensurate and incommensurate phases, alongwith
co-existence of three second order phase transitions provide evidence for the
existence of Lifshitz point.
