Mitch is an AIDS researcher who first appeared and prominated on "Tonsil Trouble". He contiunes to appear in non-speaking cameos throughout the series.
Mitch is a scientist in his 30s or 40s. He is a Caucasian male who has red hair and he wears a doctor's coat and glasses.
Mitch and his superior, Senior AIDS researcher, worked on the solution to the disease based upon Magic Johnson's money hypothesis. The two had managed to realize that if an HIV positive person is injected with cutted and crushed $180,000 into the vain, his AIDS will fade away - which finally cured both Kyle Broflovski and Eric Cartman, despite some prior disbelief voiced by his cohort.
Mitch is seen working for DNAandMe in "Holiday Special".