Yes, by “it” I indeed mean sexual intercourse, because, look, the Mushroom Kingdom has to be sustainable in some way. Someone somewhere needs to birth these abominations and they aren’t all coming from hatched eggs somewhere. Sex is a very natural part of life and occurs throughout most organisms, so embrace it. Even embrace it through the world of Nintendo which is full of nostalgia and childhood wonder.
Now if you’ve ever wondered how a goomba gets it on, well, you’ll know, because this video has shown you. It’s not even gross, this is beautiful, like a nature documentary where they pipe in sounds that no animal would ever make, but they do it anyway.