Severus stumbled into Dumbledore's office, panting and pulling at his robes. Dumbledore was startled out of his book and look up sharply. [with this sentence, try: Dumbledore, startled out of his book, looked up sharply.] Severus was drenched in sweat, his black eyes dilated. Sallow skin paled to the shade of sun-bleached ivory. Startled, the older wizard roused to the professor's aid.
"What happened?!" He asked anxiously, lowering Snape into a chair. The professor had been on a spy mission and wasn't expected back until the next morning.
"Sadism." He moaned, panting, leaning heavily against the chair. At first Dumbledore didn't understand. Then, as if struck across the face, he knew what the potion's master meant. Sadism. One of the most wretched, tortuous curses to ever be uttered.
"What...how...who?" For the first time, Albus Dumbledore was at a loss for words. Severus' breathing was slowing and his muscles were relaxing as he eased further into the plush wing chair.
"Voldemort..." He gasped out finally "thought it would be amusing. He wanted to see what would happen with the students." Dumbledore was absolutely shocked speechless.
"He casts Sadism on one of his own?" He asked incredulously.
"He was bored." Severus answered simply, reaching up to message his shoulder.
"We can't have you teaching in this condition..." He started but Severus stopped him with a wave.
"I must. This was just as much a test as it was joke. If I stop teaching he'll know I've talked to you, and you'll lose a valuable source of information." He said coldly, not without a touch of bitter anger. Dumbledore knew he was right, so he said nothing. Severus placed a hand on his chest and closed his eyes. With a sigh the headmaster gathered himself and found Severus a glass of water.
"Do you think you can fight it?" He asked finally; he couldn't lose such a valuable informant, but he didn't want his students injured either.
"Well I will have to, won't I? And before you ask, no plans have been made as of yet." Severus informed him even as he opened his mouth to ask the question. Severus remained in Dumbledore's office for a few moments more, letting his breathing calm and his head clear.
Albus Dumbledore watched the potion's master leave and sighed. Nasty business the dark arts, nasty business indeed.