Actually, its a black mage from final fantasy 1... lol Check out the 8-bit theatre. thats where I stole it from...
www.nuklearpower.com
Anyway...
I was suggesting that the cleric is not fighting the summoned creatures. He is running the hell away from them.
Then, he just needs to wait for the mage to mess up and become visible (spell or attack)... at which point the other copies of the scroll come into play.