Hey both of my guesses were indeed correct.These are mere speculations of mine, but maybe they can serve as decent approaches to their actual modus operandi:
A) They're venomous (even if these were to be venomous their color scheme/palette should be way brighter and vibrant as it is... There are poisonous frogs in real life, but their colors are flashy and vibrant as indicators of their danger. These gals colors... are way too dull).
B) That "mucus" of theirs is highly adhesive and help them ensare and immobilize potential vicims/mates (kinda like Giant Slugs do).
They're both venomous (even if their pallete do an utterly horrible and poor job at depicting that fact) and adhesive.
What can I say... I'm not a fan of this one, I don't dislike it either per se... It's just alright... just there I guess... It's not a toad (It could gain some extra points in my personal list if I were either a prince or a Qu... but alas I'm just an ordinary geek).
.P.S.: However the appearance of this one actually makes me want to believe in the potential additions of another amphibian based monstergirls like Axolotls or Caecilians (slick and smooth amphibian naga? I'm totally up to see that)