  We report a detailed observational study of the single pulses from the pulsar
J1822$-$2256. The pulsar shows the presence of subpulse drifting, nulling as
well as multiple emission modes. During these observations the pulsar existed
primarily in two modes; mode A with prominent drift bands and mode B which was
more disorderly without any clear subpulse drifting. A third mode C was also
seen for a short duration with a different drifting periodicity compared to
mode A. The nulls were present throughout the observations but were more
frequent during the disorderly B mode. The nulling also exhibited periodicity
with a clear peak in the fluctuation spectra. Before the transition from mode A
to nulling the pulsar switched to a third drifting state with periodicity
different from both mode A and C. The diversity seen in the single pulse
behaviour of the pulsar J1822$-$2256 provides an unique window into the
emission physics.

High Energy Astrophysical Phenomena