From KGB Wiki
Students are a variety of symbiotic lifeforms that feed off the education, social structure, and general scholastic wankery provided by a university or other insitution in exchange for their money. The phylum students is further divided into classes by majors and age. Evolution (by means of accumulation of credits and subsequent graduation, or use of a Moon Stone) results in reclassification into other groups. For the KGB, such an evolution often results (though not always) in defectors.
Students are medium sized grass. They receive a +4 dodge bonus to AC against Professors, and they are immune to sleep.