"It's what?"
"100% pure concentrated evil," Starlight repeated.
Twilight stared at the bottle with concern.
"I extracted it from Trixie," came the explanation.
Twilight made an uneasy but non-committal grumble.
"It's for science!"
The grumble became a sigh of resignation. "I guess. What kind of science?"
Starlight's smile got a lot less confident. "Still working on that! Which is why I need you to store this safely for a few days."
Twilight's lips pursed tightly, but she took the bottle anyway. "I'd say you should have figured that out first, but what's done is done. I'll keep it safe for you."
"Great!" Starlight beamed... for two seconds. "On a side note," she added, "Do you know a cheap foalsitter?"
Twilight's eyebrow spiked upwards with unspoken questions.
An embarrassed Starlight held up a giggling blue unicorn filly as explanation.