The Tampa Bay Buccaneers have tweaked their logo, and by "tweaked," they made the skull look more pissed off. That's about it.
If you don't believe the photo, check the team shop, which currently has the "enhanced logo" splashed all over the site. Apparently, the Bucs are also going to use a darker helmet. Hey, the Rays improved after a logo change, right?
For reference, here's the previous logo.
Update: If you can't access the shop for some reason, here's a screenshot.
H/t to Doug Kyed