The Yappies appear to be a rebellious group of Hippies that prefer to be called as a "movement" as opposed to a "gang" which they hate being called. Despite their rebellious nature, their anti-war. Crypto (disguised as one of their members) convinces them to join the Cult of Arkvoodle by saying that Arkvoodle is totally anti-war and if he had his way he would abolish war forever. Once Crypto reveals his true form to them, the Yappies are unimpressed with Crypto's look and claim he has no "spirit".
In order to prove the Yappies that Crypto's got spirit, Crypto then goes in his saucer and puts mini-buses on top of 10 buildings. Once Crypto finishes said task, the Yappies then officially join the Cult of Arkvoodle.