Sticking with the health-care theme, Cramer said that health insurer Aetna ( AET) imploded; and when something that huge falls off the tracks, "there's bound to be some real nasty pin action." The health insurance companies and HMOs saw a "crescendo selloff," meaning that everything in the group gets crushed and the selling is overdone. After one of these, everything should bounce back in bull mode as Wall Street recognizes that the selling was overdone, and that's what happened Friday, he said. But there's always a stock left behind, and that stock was HealthSpring ( HS). The stock has no defenders, no sponsorship and won't bounce back immediately, he said, making it a "major opportunity to make money." HealthSpring is a Medicare HMO that came public in February. The company made the mistake of having to lower its guidance in the very first quarter after it came public, and since then it has been despised, Cramer said. The company takes care of private Medicare for states and runs it like an HMO. This will be lucrative space, given the fact that over the next 10 years Medicare spending should grow at a compound rate of more than 9%, said Cramer. This doesn't include the new drug plan, he added. "Most Medicare is just fee for service, so it's sloppy and wasteful," he said. By joining up with HealthSpring, the company can use its bargaining power to lower costs. And in this business, "being able to contain costs is crucial." The Nashville, Tenn., company is adding new members at a torrid pace and he believes that there is a lot of room for it to grow new members. And despite its earnings gaffe, the company is good at what it does. He said that the key metric here is the medical loss ratio, meaning the percentage of premiums that a company actually needs to spend on medical costs. HealthSpring has kept its medical loss ratio at under 79%, a rate that its competitors probably wish that they had, he said.