Despite what your favorite crime show might suggest, forensic science is not infallible. As John Oliver explained on Last Week Tonight, analyses of hair, fingerprints, or semen have led juries to convict people of crimes based on what they assume is objective evidence. But there’s a lot that can go wrong with forensic science, whether because of the testimony of so-called “experts” in bite mark analysis, which is a wildly unreliable field, or because of the potential that evidence has become contaminated.

Part of the problem, as Oliver explained, is that judges and juries just don’t have the scientific expertise to decide for themselves whether forensic evidence is legitimate or junk: “It's like a cooking competition for toddlers hosted by a stray cat and judged by goats.” Jurors in particular tend to accept the findings of lab technicians as fact, thanks to what they see on television, where a DNA sample is almost always the answer and no one has to worry about whether there were golden retriever hairs mucking up the results. Considering that people’s freedom—and even their lives—depend on a fair trial, that’s a big problem.

Prosecutors call this influence “the CSI effect,” so Oliver imagined what crime shows would be like if they were honest about the unreliability of forensic evidence. The result is CSI: Crime Scene Idiot, starring Josh Charles as a forensic scientist whose phony evidence is matched only by his terrible, inappropriately timed puns.