Youk had the Holy Handgrenade of Antioch, which he intended on using on the Rays after saying "Bless this, O Lord, that with it thou mayst blow thine enemies to tiny bits, in thy mercy."
It all started when Manny insisted on pulling the pin. Youk was OK with it and gave him these instructions: "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."
Manny, being Manny, pulled the pin and counted "one, two, five...
...and it was all downhill from there.