Vorpal

vorpal, vorpal sword, adj., D&D-ism 1. (nonsense word) the type of sword carried by the hero of the poem "Jabberwocky," from Through the Looking Glass and What Alice Found There by Lewis Carroll. 
2. in D&D, a sword that always decapitates when it hits.
Ex: I decapitate Asmodeus with my vorpal sword. 
3. a prefix or descriptive to indicate that something does a great deal of damage.
Ex: Every game he gets a paper cut. It's like he's got a vorpal character sheet or something. [GJ1]