She pulls a Kazuma!

"But first, you need to offer me a wager," Megumin told Yunyun. "My usual offer of my place as best in our generation will be my collateral, but your lunch won't cut it now that I am eating enough these days without it."

"How about this then?" Yunyun asked, pulling out a small crystal, Kazuma noting that it looked valuable. "Premium Manatite!"

"Acceptable! You're on!" Megumin declared, casting aside her staff.

"Perfect!" Yunyun grinned confidently. "Once I win, I can finally claim my... title..." she trailed off as Megumin approached, and Yunyun got a good look at her. "...um... Megumin... Is that?"

"Indeed, it is toad slime," Megumin smirked evilly, still covered in the stuff. "Don't mind me, I'm good to go! Now come fight me! Once you get close, I shall pin you in my embrace!"

"N-now hold on!" Yunyun shuddered, freaking out. "You... Yeek! You're just trying to make me not want to fight you! It... It won't work!"

Her resolve shattered the moment Megumin latched onto her. "Come on... Aren't we friends? And do friends not share each other's burdens?"

"Nooooo!" Yunyun shrieked. "I give, I give, just let go of meeeeeee!" She then proceeded to run away, dropping the Manatite after Megumin released her, smirking deviously.

Megumin picked up the Manatite, and grinned. Kazuma stared at her sternly. "Megumin, for shame... That was just underhanded..." Just as Megumin turned an "Are you kidding me!?" expression towards him, Kazuma dropped the stern facade, and grinned. "I'm so proud of you!"

The two cackled evilly together as they headed back towards the mansion.