A/N: This prompt was given by CinnamonPenguin. I hope it lives up to your expectations.
Ladybug and Chat Noir were lounging on a rooftop after sunset when an idea came to the former's mind.
"Chat?" she said, facing her partner curiously. "Can I test something out?"
"Whatever you'd like, my lady," the cat-themed superhero said with a suggestive wink, resulting in an eye roll from his partner.
"I'll be back in a minute."
Ladybug swung away, returning moments later with what appeared to be a potted plant. Chat tilted his head curiously at her.
"We should know if this works," she explained before he could ask. "It's always good to know our weaknesses in case of a related akuma."
"If what works?" Chat Noir asked. "I'm pretty sure my weakness isn't basil."
Ladybug scowled. "It's catnip."
That changed things considerably. Chat leaped up from his perch, backpedaling wildly and scampering as far from the offending plant as possible.
"LB, that's dangerous! Don't you know the smell of catnip is supposed to make cats go crazy? I'm already crazy for you as it is; catnip would just be overkill, don't you think?"
Ladybug sighed at her partner's antics. "We need to know our weaknesses," she said simply. Holding out the plant, she hesitated, then added, "It can't be too bad. Come on, Chat."
"I warned you, Bugaboo," her partner sighed dramatically. He approached the outstretched herb tentatively, reaching out to take it.
"Smell it; eat it; do something," Ladybug urged unhelpfully.
"Isn't that illegal?" Chat quipped, receiving an unamused glare from his partner.
He did as she asked, though, bringing the plant to his level and eyeing it like a real cat would. Despite the light mood, he was still afraid of just how similar to a cat he was. Petting, purring – that, he was more than fine with. But catnip?
Ladybug was just as worried, perhaps more so. She didn't want to be responsible for making Chat Noir go insane. She hoped it wouldn't last long.
There was only one thing to do.
"Well… here goes nothing," Chat said, and sniffed the leaves of the catnip.
The superheroes waited with bated breath.
And waited some more.
"Huh. Guess not. What a shame…" Chat Noir grinned at his partner, who exhaled deeply.
"That's a relief," Ladybug said slowly, "but it's… weird."
"Definitely weird," Chat agreed.
"Well, would you care to take the catnip home with you? I don't have much of a use for it."
Chat Noir's eyes lit up. Catnip or not, having a gift from his lady would make it seem as though the herb worked on him after all.
"It would be my purrleasure."