He resolved to hold off on grading the paper until he could talk to Daria and find out what was going on. That time came upon asking her to stay behind the next day after class.
"Daria, I'd like to talk to you about a number of bizarre typos in your paper."
"I don't think you can call them typos if I wrote it out by hand," Daria pointed out.
Mr. O'Neill nervously chuckled and pressed on. "Daria, I think the problem is that you're not crossing your Ts."
A terrified look suddenly showed up on Daria's face. "I...I can't!"
Mr. O'Neill smiled affably. "Sure you can, Daria!" He turned to the chalkboard and drew a long vertical line on it.
"Please, don't!" Daria cried out.
It was too late. Mr. O'Neill capped off the line with another horizontal one. "And now you've crossed the T."
Mr. O'Neill looked down. For some reason, a gore-covered hand was protruding from his chest, holding his still-beating heart. "Oh my!" Mr. O'Neill said in shock, before he fell over dead.
Behind him, Mr. T threw down the teacher's organ and gave Daria a stern glare. "Remember, Daria, nobody crosses the T and lives." Daria vigorously, fearfully, nodded her head.