Setup: buy 1 ATM call, sell 2 calls 5–10 points OTM, same expiration. Best result is the stock pinning to the short strike at expiration — max profit there. Above the short strike, the position turns into a naked short call and bleeds. Below the long call's strike, the structure expires worthless (or at the credit collected, if any).
Use case: high-IV environment where you have a moderate bullish bias but don't expect a big rally. The credit-or-zero-cost setup means a small move up captures profit, while a flat or slightly down move costs nothing. The unbounded upside loss is the catch — size carefully and have a defensive plan if the stock breaks through the short strikes.