Now this is a full on ritual:
I'm surprised it doesn't start "First you catch your possessed..." because honestly, any demon worth it's salt would have buggered off before the litany of the saints.
PRIEST: ...It is He who commands you, He who once stilled the sea and the wind and the storm. Hearken, therefore, and tremble in fear, Satan, you enemy ofthe faith, you foe of the human race, you begetter of death, you robber of life, you corrupter of justice, you root of all evil and vice; seducer of men, betrayer of the nations, instigator of envy, font of avarice, fomentor of discord, author of pain and sorrow.GEF somewhere overhead snorts, then begins to laugh uncontrollably.
GEF: I'm sorry, I can't go on. You forget render of chickens, protector of Voirrey, eater of porridge, teaser of dreary old men and stuffy vicars! You be gone, oh sir of little faith!
A book is tossed at the Priest, followed by a cowbell and a candle.
I don't know if Gef would be all that good humoured and I doubt he would wait until near the bitter end to interupt an exorcism.