Giving a weapon the Shuriken animation

"The data and offsets Fenrir posted, I can find them but couldn't get any visual change, at least as far as I could tell, by changing some values. I didn't go as far as changing the entire block to one value, but as I said I couldn't get a response from the poking I did to that data."

Works for me, I've altered quite a few weapons. I made a spear out of a dagger. So when throwing this weapon with the Throw command or jumping with the Jump command, instead of a dagger appearing, its a spear.

I've never tried, but I believe that you can't turn non-weapons (shields, helmets, armor, relics, and items) into weapons. The information above only applies to weapons.

The default thrown weapon is a dagger, you could throw a helmet, but its animation would be that of a dagger. Again, I remember trying to make the Rename Card into a weapon and ran into complications a few years ago.