It's no secret that using public transport can be a minefield, as you can and often do get seated next to less-than-pleasant fellow travellers.
She later took to TikTok to shame the woman for her actions, sharing a video of her, masked, alongside a caption that read: "To my in-flight seat buddy Cathy who decided to text her friends about 'sitting next to a fat a**’ omg' on my BHM-ORD flight: make sure you turn your brightness and font size down next time."
As the caption suggested, Mika is of the opinion that if you're going to send a mean message about a stranger, you should do so in a subtle enough way that there is almost no chance of them seeing it.
While some people might assume that Mika only shamed the woman on TikTok, but she also called her out in real life, as she revealed in a follow-up video.
The TikToker recalled: "Cathy sent this text message and I immediately just went: 'If you're going to call someone fat sitting right next to you, you could at least turn your brightness down.'
"And she looked at me and said: 'You weren't supposed to see that.' And I was like: 'Well you didn't make it very un-obvious.'"
While the situation was already seriously awkward at this point, it got worse when Mika asked for a seatbelt extender.
This led to a brief miscommunication with the flight attendant, who worried that she was the one being called out and not the rude passenger.
But Mika assured her that she was not and proceeded to decline her offer of a change of seat.
Why? We hear you ask. Well, she wanted to teach Cathy an important lesson.
"I said: 'No, ma'am. I'm fine. I'm going to sit right here, for the rest of this flight,'" Mika remembered. "Maybe Cathy won't do that again."
As you can imagine, the incident went far from unnoticed since it was posted to TikTok about a week ago and has been viewed well over two million times.
Praising Mika, one viewer wrote: "I am so glad you said something… and didn't move seats."
"Good for you!!! Make her sit there in the discomfort of knowing she messed up!" added a second while a third remarked: "Yesss! I admire your confidence. We need to start calling out peoples horrid behaviour [sic]."
"This would have hurt my feelings immensely," admitted a fourth. "The way you handled it is a lesson is pure class. You are my hero."
How do you think you'd have reacted in Mika's shoes?