Adapter get really hot?!

[DotCom2]

When I plug my iPhone into an electrical outlet using the Apple supplied adaper and USB cable, the plug part gets really really hot.
Is this normal or should I be worried.

 

[-aggie-]

That's not normal. Get it replaced.

 

[DotCom2]

That's not normal. Get it replaced.

Oh GREAT
Usually I just plug the phone into an USB port on my PC to charge but today I used the adapter and noticed it was really hot to the touch.
This is the replacement one from Apple with the green dot so I dunno.
Maybe I better email Apple???
There isn't an Apple store near me.
Or should I go to the AT&T store where I purchased it?