Bashing your head on a block of tofu
Translating from Japanese can sometimes be a little confusing. It'd be easy to make a 'Lost In Translation' joke here, but there are idioms and phrases that are just... puzzling. I'll give you an example:
Now, that ('toufu no kado ni atama wo butsukete shine') literally means 'go bash your head on the corner of a block of tofu and die'. It's the Japanese equivalent of 'go take a long walk off a short plank', more or less.
This is an unusual phrase for several reasons. First off, it's pretty difficult to hurt yourself on tofu. I don't know if any of you have ever tried this. (I sure haven't, in case you're curious.) Even if you fried it for quite a while, that tofu's still going to have a soft and squishy consistency. Bashing yourself on any part of the tofu is a tall order.
And if we're going to go with the corner of the block, why bash your head on it? Wouldn't trying to take your own eye out on a sharp and hazardous tofu corner do much more damage? I don't think it's possible to give yourself a lobotomy with a soy-based food product.
All of this is without even covering the effort it would take to draw blood, let alone mortally wound yourself. It reminds me of 'The Horribly Slow Murderer With The Extremely Inefficient Weapon'. (Fair warning, probably NSFW. Contains a lot of spoons.)
Maybe that's the point. The person who tells you to connect your head with some pointy tofu post haste probably wants you to suffer. Considering how difficult it can be to say what you really mean in Japanese, this phrase is most of the way there.