Short for oxycodone, not OxyContin which is actually a brand name. It's an opiate found in Percocet (with APAP), Percodan (with Aspirin), OxyContin (a time released form), and a few other brands as well. It is stronger than codein and hydrocodone, and some say it beats morphine as well. It's not as strong as oxymorphone (which you have to inject or take up the butt) or hydromorphone or heroin, but it's some lovely shit anyway
A pill popper is a certain type of drug addict who doesn't care if they live or die and doesn't care what they take. They'll take muscle relaxers, opiates, amphetamines, benzos... anything in pill form. They enjoy the actual act of taking a pill and don't much care about the effects. They should not be confused with people who take drugs that happen to be in pill form.
That pill popper is such a dumbass he thought he got high off a laxative