A form of pill popular in early 90s rave culture, where extacy was supplied in yellow and green capsules, named after a popular song at the time. see also Dennis the Menace
"Hey man, what you got"
"I got some Rhubarb and Custards, deck one of these and you will have eyes like dinner plates"
A hardo is a person who tries extremely hard at everything. Most times a hardo will try very hard at things that do not require excessive effort. For example, sports practices, gym class, etc.
Wow did you see Jack at practice today? What a hardo!