OUMNH: Atlantic Bluefin Tuna
More threatening-seeming in large.
This may seem pretty savage, but it is just a tuna... They're amazing fish, but certainly no threat to humans. This specimen is 168 years old, and has been on display in the OUMNH since it first opened.
I had a quick wander around the Museum of Natural History in the early afternoon (sanity break...); I had fun photographing this tuna (closer alternative), as well as the march of mammals (can you guess what the closest one is?) and the rather stunning waxwing in a bell jar (and the reflections on its case).