A Happy Accident

Those of you of a scientific persuasion will recognise this mage instantly. The rest of us might struggle.
 
Clue. Where did I find it? - at the bottom of a cup of green tea left some time ago in the corner of my studio.
 
Yes its mould. 
 And this is how penicillin was discovered.
 
Scottish bacteriologist Alexander Fleming accidentally discovered the antibiotic in 1928, when he came back from a vacation and found that a green mould called Pennicilium notatum had contaminated Petri dishes in his lab … and was killing some of the bacteria he'd been growing.
 
Today penicillin is the most widely used antibiotic in the world.