Decades ago the Balinese tiger was living here, now there are only a few poisonous snakes and some other kinds of scary animals that are not really dangerous.
Scorpions are very small and their sting is more like a bee sting. Unless you are allergic, there is nothing to worry about. A place where you can encounter them is between stones on the wall of the outdoor showers and between your folded laundry. Related to spiders I've never heard that one of them is toxic, but some can be quite big. If you kill a spider it brings misfortune, but if you have in your home it brings good luck Balinese say
About Geckos, the kind that occurs in Bali is only the Tokek variant. They are quite large and have a very distinctive and resonant call which sounds a lot like "fuk u, fuk u, fuk you," repeated several times until only a simple "you, you" remains. They are amazingly colored animals and seemingly endless variations, and with eyes like jewels. When running around on the ceiling they sound like a herd of elephants is running around. They have a very curious habit they always, and I mean always poop in the same place. Play not with them because they have a very nasty bite and they keep hanging in your skin.
Furthermore, there are numerous species of lizards found, including some big big dragons, but all very innocent, though they do bite.
