Miraculous Mermaids (discontinued, but check the last chapter for extra info!)

3

"Hey! You made it!" Adrien and I turn our heads to see who talked to us. It was Alya.
"Of course we did, silly!" I teased. "I doubt that we would be your friends of we didn't."
"Mari's right." Adrien added with a chuckle.
Alya raised an eyebrow. "Mari?" she asked before taking the gifts from our hands and pulling me away. "Mari?!" she squealed.
"I don't know either! We were talking then all of a sudden he dropped the 'Mari' bomb on me. Not that i'm complaining." I giggle.
"Oooh girl, today will be in-ter-es-ting!" Alya says before running off to put the gifts on the gift table. I look for a place to sit before I spot the perfect chair. It's in the back, farthest away from the pool ensuring that I won't get splashed  but still in sunlight.  I set myself down and start to observe. Everyone's here. Even Chloè. But that was Alya's parents' fault. It was one of the rules that was put on her party. 'Everyone must be invited'.
Anyways, just as I was getting comfortable, I hear the words i've been dreading to hear all morning.
"Marinette, come out and swim with us!" I sigh and call back to Alya.
"No thanks!" I call back.
"Please?"
"Sorry, Alya but I just..." I trail off as I think of an excuse.
"You just what?" I can see that Alya is actually a little hurt.
"...I just...pools aren't really my thing y'know?" This is the truth. Because of the chlorine, the pool water always makes me feel sick even though my gills filter the water.
"Good! Marinette will probably ruin the water anyways." Chloè sneered. Although this remark hurt, I was glad Chloè backed me up without meaning to. 
"Chlo, come on." Adrien said. "Don't be like that."
"Be like what, Adrikins? It's the truth."
"It's fine everyone," I say. "I'll get in the hot tub but that's all." Alya grins as I slip off my cover-up.
"Marinette, what are you doing?" Tikki asks.
"Don't worry Tikki, the bubbles will hide my tail." I respond.
"Ok but what if others want to join you?"
"I'll put the heat up to a point that no-one will want to get in."
"...alright."
I smile and give Tikki her cookie before walking over to the hot tub. I turn up the heat and set the bubbles to a maximum. Taking a deep breath, I step into the hot tub quickly sitting down. Instantly, I feel my legs merge together and pink scales erupt on my skin. Nervously, I look around to see if anyone noticed. Thankfully, nobody did.
"Hold up girl, i'm commin' to join ya!"
Oh no.
"Uh..You might not want to do that." I say.
"Huh? Why wouldn't I-- ouch!" Alya yelps. Mare, the water's so hot! How can you stand this?"
"It can't be that bad." Nino says. "Woah, it is that bad!"
"C'mon guys," Adrien starts. There's a reason why hot tubs are called hot tubs--yeouch!" he yelps before jumping out the tub. "Alya's right, Mari. How can you stand this?"
There it is again. Mari. "I don't know what you're talking about." I say a light blush forming around my cheeks.
"Hold on, are your knees pink?"
"Uh...y-yeah! Um...ah...because of the heat! Haha!" I stutter my blush becoming darker.
"I'm adjusting the temp." Alya states.
"No, don't!" I shout. "If you do, I'll get out of this tub." I threaten.
"..fine..."
"Thank you!" I say cheerfully. The tub was hot. Extremely hot actually. But nothing I couldn't handle. Finally, it was time to head inside for some cake.
"Mare, get out of the tub! It's time for cake!" Alya calls.
"In a sec!" I call back. "You guys go inside without me."
"...Ok." Alya closes the door and I get out of the tub. After a minute, my tail has disappeared into legs and I walk inside ready for some cake.