After introducing dangerous sharks, here a harmless one.

Scymnodon ringens
knifetooth dogfish (Scymnodon ringens). Image by Henk Heesen, taken from This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License

But hold on! The teeth look dangerous, doesn’t they?  But this rare, medium sized shark is indeed considered harmless (not that little means automatically harmless, look at the cookiecutter shark), despite its name: knifetooth dogfish.

The knifetooth dogfish (Scymnodon ringens) lives in the deep sea in the Eastern Atlantic and Southwest Pacific and is up to 3.6 ft – 1.1 m – long. It looks, with the exception of its teeth, like a relative of the pocket shark or the ninja lanternshark, but it is actually a species of sleeper sharks (like the Greenland shark). It is used for dried or salted meat and fishmeal.

Teeth must be really something distinctive, since there is a sleeper shark called sparsetooth dogfish, too.

Sources: here and here