Aint No "Hmm" About It

The flare of brilliant light arches and pulses, crackling right where the thing's head is forming. It blasts against the top of the form, little rivulets of unrelenting light - that pulsate in frustration as the fiend attempts to resist them!

(The fiend has spell resistance 8, that would mean rolling a d20 and adding your level to get an 8 or better if you want this to work. Except that the fiend also has blindsight, so it doesn't matter.)

The creature is moving even before it fully forms. It is of a bat-shape, but one with a wingspan of seven and a-half feet. A breath of sulphur and decay emanates from it sharp teeth, and its reddish hellfire eyes wince at your spell. But its wide, obsidian ears swivel directly at you, and you can tell that it does not need its eyes to find you, not in a room this small in any event.

"You knew, mortal flesh," it grates in a voice that sounds like a thousand dirty knives skittering down a slate of chalk. "You knew that this was not your place, and yet you came."

A wing swings out, catching Kaspar in the chest with a sickening crunch. Flimsy it looks, but it is not. Kaspar takes...(oh my) 10 hit points of damage. The alchemist's fire that he had been preparing is dashed into a corner, where it merrily burns against the wall, making mocking shadows. (How's that for explaing your natural 1?)

"You are food," the creature laughs. Its skin ripples, and you feel its evil rising, like a dying man preparing to choke on his own vomit. "Foolish, foolish food." Its forked tongue licks out, tasting the air that is ripe with your sweat.