I also liked this one, on how easily a program became adversarial with its implementer:
To do so, he tried to turn off all mutations that improved an organism’s replication rate (i.e. its fitness). He configured the system to pause every time a mutation occurred, and then measured the mutant’s replication rate in an isolated test environment. If the mutant replicated faster than its parent, then the system eliminated the mutant [...] Replication rates leveled out for a time, but then they started rising again. After much surprise and confusion, Ofria discovered that he was not changing the inputs that the organisms were provided in the test environment. The organisms had evolved to recognize those inputs and halt their replication. Not only did they not reveal their improved replication rates, but they appeared to not replicate at all
I also liked this one, on how easily a program became adversarial with its implementer: