It's his fist.

In the instance before Mario makes contact with the block, in a span of time so minuet and insignificant it has to name, Mario turns into his true self. He sheds the cloth and flesh of his lure and pulls back his adamantium line, reveal himself for the fisher he is. He then takes the cube, replaces it with a brown one, and places an item on it. he then retreats to his space behind the screen, and continues his fishing.

I used to think it was his head, and then I saw the cartoons. Childhood turned upside down.

It's his fist, but I want to believe it's his head. I need that.

So wait..... Is Mario actually Ryu in disguise? Hmmmmm

@guesty_01:

You've got it backwards. Ryu is actually Mario in disguise.

Head and he still is the smarter brother.

I always assumed he was using his head.

I have never laughed so hard in my entire life.

Though to be fair, wouldn't it be Shoryuken?

Mario hits the block with his...

...head, which is why he's the shorter brother.

...fist, which is why he wears such big gloves, because his fists are swollen.

@video_game_king said:

Maryu?

Mari-OH-ken.

Yoshi Fire.

I've never even considered that he might be using any other body part except his head...

All of you who voted head is in denial, you know it's his fist!

He even grabs on to his hat in super mario world as he falls, using the very same hand that he just used to hit the block above him. (if I remember correctly)

@video_game_king: Shit, you've blown my mind. That's changed my entire outlook on video games.

Always thought it was the head until I found out some years ago.

Ever since Mario was conceived he's always been hitting the bricks with his fist. The animation has always been that way.

@cornbredx:

http://m.ign.com/wikis/super-mario-3d-land/Wearable_Coin_Block

I think it's his head but I know it's his fist.

I always think about it as his fist hitting the block. Perhaps because Super Mario Sunshine was my first 3D Mario game and if I remember rightly, he clearly hits the blocks with his fist in that.