  We present a detailed study of V899 Mon (a new member in the FUors/EXors
family of young low-mass stars undergoing outburst), based on our long-term
monitoring of the source starting from November 2009 to April 2015. Our optical
and near-infrared photometric and spectroscopic monitoring recorded the source
transitioning from its first outburst to a short duration quiescence phase ($<$
1 year), and then returning to a second outburst. We report here the evolution
of the outflows from inner region of the disk as the accretion rate evolved in
various epochs. Our high resolution (R$\sim$37000) optical spectrum could
resolve interesting clumpy structures in the outflow traced by various lines.
Change in far-infrared flux was also detected between two outburst epochs.
Based on our observations we constrained various stellar and envelope
parameters of V899 Mon, as well as the kinematics of its accretion and outflow.
The photometric and spectroscopic properties of this source fall between
classical FUors and EXors. Our investigation of V899 Mon hints instability
associated with magnetospheric accretion to be the physical cause of sudden
short duration pause of outburst in 2011. It is also a good candidate to
explain similar short duration pauses in outburst of some other FUors/EXors
sources.

Solar and Stellar Astrophysics