Recent development on supernova research has confirmed that there is a distinct class of events which are more luminous than canonical core-collapse supernovae (CCSNe). Typically they show a broad peak (~ -21 mag) with a shallower decline rate than normal events. SN 2012aa, which was discovered in a relatively distant (redshiftz ≈ 0.08) host galaxy on 29.6 January 2012 UT by the Lick Observatory Supernova Search (LOSS), has similar characteristics. The event was also detected by the Catalina Real-Time Transient Survey (CRTS) during its rising phase, with peak apparent unfiltered magnitude ~ 18. From optical spectra it was characterized as a Type Ic SN, although photometrically it is quite distinct from canonical Type Ic events. The photometric and spectroscopic follow-up over a span of 100 days clearly shows the signature of interaction of the SN-shock with the circumsteller medium (CSM). The post-maximum decay rate of this event is roughly 0.012 mag/day. This is much lower than that of normal stripped-envelope CCSNe (~0.06 mag/day) and comparable to the decay rate of  superluminous events like CSS100217 and SN 2007bi. However beyond 60 days, the decay rate becomes comparable with that of radioactive 56^Co. Here, I shall present the optical photometric and spectroscopic follow-up observations of this event, along with detailed analysis of the light curve and spectra, which demonstrate the interaction of SN-shock with the CSM.