We were visiting a small village near Oaxaca, on a Thursday, and there was a festival planned for the following weekend.  Several young men were dressed in these hideous masks and totally drenched in dirty motor oil.  They were making their way through the streets.  Being a photographer, I naturally walked up to them and starting taking pictures.  They apparently DID NOT like that!  They surrounded me and kept coming closer with their oil soaked bodies.   I asked for an explanation but with mediocre Spanish and the muffled voices from under their masks I could not understand what they were saying.  I eventually managed to escape without oil touching my camera but my clothes were not so lucky. 

Anyone care to explain the custom here?

mike@digitalartsphotography.com