British designer Tamsin van Essen has created ceramic cups that appear to have been colonized by various bacteria. Pictured above is streptococcus. No matter how thirsty I was I couldn't be convinced to drink from that vessel .
The raw clay for these cups was contaminated with various 'foreign' materials, to mimic the growth and multiplication of bacterial colonies. Bringing the microscopic to the macroscopic level, the contamination spread in an uncontrollable way during firing.
Link - Via Book Of Joe