TITLE: GCN CIRCULAR NUMBER: 7311 SUBJECT: GRB 080212: VLT optical rapid decay DATE: 08/02/14 19:37:21 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo, D. Fugazza (INAF-OAB), L.A. Antonelli (INAF-OAR), S. Covino, G. Chincarini, C. Guidorzi, G. Tagliaferri (INAF-OAB), V. D'Elia, F. Fiore, S. Piranomonte, L. Stella (INAF-OAR), M. Della Valle (INAF-OAA), S. D. Vergani (DIAS-DCU) report on behalf of the MISTICI collaboration: We observed the optical afterglow of GRB 080212 (Ziaeepour et al., GCN 7296) with the ESO-VLT equipped with the FORS2 camera in imaging mode at three different epochs. Observations have been carried out in R-band on Feb 13.3101 UT, Feb 13.3682 UT and Feb 14.2838 UT (0.58, 0.64 and 1.55 days after the burst, respectively). We found that between the first two epochs the afterglow faded very rapidly, with a decay index of alpha ~ 5.5. Very likely, the afterglow underwent a remarkable increase of its optical/NIR flux, probably related to the brightening observed in the X-rays about 4 hours before our VLT observations (see D'Avanzo et al., GCN 7310). Assuming the above decay index, we estimate R ~ 20.8 at the epoch of the REM detection (D'Avanzo et al., GCN 7302) with an implied colour R-H~5 The decay of the afterglow then slowed down between the last two epochs and we measure R~25 in our last observation.