Fandom oneshot book [Requests open]

[Cookie Run: Ovenbreak] Yandere! Lychee Dragon Cookie x Reader

As I was writing this I found out that Lychee Dragon is never referred to by any pronouns... I looked on the fandom wiki to make sure I had them right and was concerned when it just said "unspecified".  I used they/them for this.

Requested by: my brain the second I played the new chapter a few days ago.
I wrote the whole thing this morning—

"(C/F) Cookie! (C/F) Cookie!" Mangosteen Cookie runs over to them, "Let's play a game!"

"I can't right now Mangosteen Cookie." They barely turn their attention from the boat they were trying to fix. The sooner they get off this island the better... They worried what might happen if they stayed.

"But it will be fun!" Mangosteen Cookie grins.

"There are Cookies in the village you can play with." They continue to try and ignore the childlike persistence. "Why don't you go play with them?"

"Because I want to play with you!" Mangosteen Cookie's voice holds a force that seemed uncharacteristic of the normally bubbly and silly Cookie.

It made (C/F) Cookie's dough crawl with fear.

"Now c'mon! Let's go play!" And just like that they were back to a cheerful happy tone.

"I'd..." (C/F) Cookie barely glances at the smiling child, but as soon as they do, it feels like their head just went completely numb.
"Ok! Let's go..."

"Yay!" Mangosteen Cookie leads the way deeper into the island.

What just happened?

"Mangosteen Cookie, isn't this the way to the cave Rabutan Cookie specifically told us not to go near?" When their mind seems to clear, that was the very first thing they realized.

"It will be fine, trust me!" The child waves off any concern, "Now let's play hide-and-seek."

The numb feeling in their head returns.
"Ok!"

"I'll go hide, and you stay here and count, ok?" Mangosteen Cookie smiles.

"Alright. 1... 2..."

After a few rounds of hide-and-seek, (C/F) Cookie couldn't find Mangosteen Cookie at all.

"Alright Mangosteen Cookie, you win." They sigh.

"Hurray!" The child jumps out of their hiding spot, before slipping and tumbling over almost falling off the cliff, with (C/F) Cookie grabbing them just before they fell. "Thank you, (C/F) Cookie."

"Be more careful." They start walking back to the beach, more specifically to the boat that Mangosteen had dragged them away from.

"Wait! But I want to keep playing!" Mangosteen Cookie whines.

"And I want to keep working on my boat." They grumble. "I'm certain you can find someone else to play with."

"But they won't be as fun as you..."

"I'm not very fun though." (C/F) Cookie glances at the child, confused.

"But you are! You're so much fun!"

"Is that why you insist upon teasing me so much?"

"Teasing you?" The kid questions, "How am I doing that?"

"You take my tools, randomly drag me around the island, and then deny you ever did either of those things..." They list.

"But I didn't!" Mangosteen Cookie frowns.

"I literally saw you take the hammer I spent all of yesterday looking for!"

"That wasn't me!"

"Uh, so there's another Cookie who looks exactly like you?" (C/F) Cookie crosses their arms