This is a great weapon and is handy for dispatching white rabbits in caves. See the following for example.
After the rabbit attacks.
ARTHUR: Right. How many did we lose?
LAUNCELOT: Gawain.
GALAHAD: Ector.
ARTHUR: And Bors. That's five.
GALAHAD: Three, sir.
ARTHUR: Three. Three. And we'd better not risk another frontal assault. That rabbit's dynamite.
ROBIN: Would it help to confuse it if we run away more?
ARTHUR: Oh, shut up and go and change your armour.
GALAHAD: Let us taunt it! It may become so cross that it will make a mistake.
ARTHUR: Like what?
GALAHAD: Well... ooh.
LAUNCELOT: Have we got bows?
ARTHUR: No.
LAUNCELOT: We have the Holy Hand Grenade.
ARTHUR: Yes, of course! The Holy Hand Grenade of Antioch! 'Tis one of the sacred relics Brother Maynard carries with him. Brother Maynard! Bring up the Holy Hand Grenade!
ARTHUR: How does it, um-- how does it work?
LAUNCELOT: I know not, my liege.
ARTHUR: Consult the Book of Armaments!
BROTHER MAYNARD: Armaments, chapter two, verses nine to twenty-one.
SECOND BROTHER: And Saint Attila raised the hand grenade up on high, saying, 'O Lord, bless this Thy hand grenade that, with it, Thou mayest blow Thine enemies to tiny bits in Thy mercy.' And the Lord did grin, and the people did feast upon the lambs and sloths and carp and anchovies and orangutans and breakfast cereals and fruit bats and large chu--
MAYNARD: Skip a bit, Brother.
SECOND BROTHER: ... Now did the Lord say, "First thou pullest the Holy Pin. Then thou must count to three. Three shall be the number of the counting and the number of the counting shall be three. Four shalt thou not count, neither shalt thou count two, excepting that thou then proceedeth to three. Five is right out. Once the number three, being the number of the counting, be reached, then lobbest thou the Holy Hand Grenade in the direction of thine foe, who, being naughty in my sight, shall snuff it."