I was trying to figure out how to correctly do AttributeModifiers, but in the process I accidentally set Operation to 3, which isn't a valid Operation. Just having the item in my inventory caused the game to crash. I kept having to delete the item using NBTExplorer in order to load the world again without crashing. I eventually realized my mistake and set Operation to 1.

Here's the command I used:

/give @p beef 1 0 {AttributeModifiers:[{AttributeName:generic.attackDamage,Name:noDamage,Amount:-1d,Operation:3,UUIDMost:20l,UUIDLeast:10l}]}