It is a shock but if the original mangaka is slipping Japanese slang that is used in a similar I could see it as justified. I think it's to easy to forget that dumb internet slang isn't unique to english.
Bro...... you can't have a low angle shot of someone's feet dangling off the ground while the MC is looking on with a shocked expression... shit gave me a heart attack.
I kinda dislike when artists make mermaid tails look like they're just legs inside a costume like on page 5. You can clearly see that the taill is bending like as if it has leg joints.