Spamton G. Spamton. He encounters Rosie like he encounters Kris. But....he's more interested in her Miraculous rather than her soul.

And since that encounter, she can't get rid of him.

Until...he offers to sell her the thorn ring.

She buys it after hearing what it does.

It increases your magic to its full potential, at the cost of putting you in constant agony. 

But....Rosie had to have killed a Tom of people for it, and 682 and her get into a fight about it.

The next time Spamton sees her....he takes FULL advantage of how upset she is.

"Ah, [His Voice] ran out on the [receiver], didn't it [Little Sponge?] You screamed and cried that he didn't understand.  You [×$@!]ed yourself [BIG SHOT] time. You will never come back from this, you know. [HE HATES YOU] is what I'm meaning to say. You bought my [specil ring] for the price of [My Favorite Year!] How many people did you kill for it? [Tell me.] Tell me how many people you [ERASED FROM THE FACE OF THE EARTH] for that ring. You're an [ABSOLUTE MONSTER.] Why don't you just give up on being a hero? Sell me [The Miraculous!] For the price of [Your Favorite Year!] You never deserved them anyways."

Rosie breaks at this, sobbing. She cries out,  sobbing in regret. She almost goes through with the deal, until....

"Hey, does it [smell] like rotten eggs, or is it just me?"

And 682 mauls Spamton for breaking his sister mentally like that.

[Rosie....no argument ever will split us apart. You're my sister, no matter what. You're safe with me always. Spamton was never right. You never were a monster. You did what you had to.]

Rosie smiled softly through the tears. She never was a monster.