Forget the OtterBox and just make yourself a LEGO iPhone case. Your 9-year-old self would be so impressed. But it might actually be a better protector.
Dropping an iPhone 6s with a case made out of LEGOs from 100ft in the air, TechRax proves that LEGOs aren't just for kids. Although the case itself shatters on impact, the iPhone comes out functioning perfectly, with no cracks and no frame damage besides a knick on one corner. All in all, success. Unless you're really attached to the LEGOs.
Take a look at the video to see the drop and results. Then maybe get your bricks out of storage.