If Experimental->Game nerfs->Nerf mending is enabled,you can put enchantments on incompatible items(like Protection on a Pickaxe)
1.Get an enchanted book with mending and an enchantment that is incompatible with the item of your choosing
2.Put the said enchanted book on the incompatible item in an anvil
3. Congrats,you have created a cursed item!

When doing this,enchantments don't upgrade: if the item has Efficiency 4, and the book has Efficiency 4,the item does not get Efficiency 5 after putting on the enchanted book