I received this from a friend who said they used to play with it in the water. I got a bit worried that the toy could have mold, due to that information and the black spots. But when I keep inspecting the toy or asking a friend, they all say it could be ink because "mold doesn't do that", but I know, from my school lessons and research, that mold can in fact ingrain themselves in plastic. So I decided it's better to ask in a place where it could be identified.
I also tried using a microscope I had to check and take pictures, some of them are kinda bad due to the screen glare..
Additional information: I have already soaked the toy in warm water, mixed detergent in and scrubbed it before leaving it in the pot for 30 minutes. Then, I scrubbed the toy once more with detergent, washed it, dried it up with a cloth then a blow dryer and put it in the napkin on the picture.