MacBook Pro MagSafe Charger - Kinks/Rings
This happened to my previous chargers, but not quite this bad.

The reason is wrapping the wire too tight around the charger and moving the little hook back and forth.

It can't really be fixed and the cable will break and tear. You can try going to the Apple store for a replacement, but without extended warranty I failed.

Until it break/cracks there's no real danger, after it breaks there's a mild chance of shock. I've fixed mine with Sugru, any silicone putty would work. I've seen quite some people use gaffer tape and the like. There's also specialised shrink sleeve products to fix it.

After the plastic breaks and no fixes are applied, the inner cable might start to fray and eventually also fail.