Triggers are awesome like that. On the reef, too; very interactive. They're usually fun, but not always.
Years ago, when I first started diving overseas, I went to a couple of places in Fiji for shore diving. I'd been an aquarist and knew the relevant fish species, but didn't know about
everything I might encounter on a reef. So I'm doing a dive, just me and the divemaster (it was off-season), and I see this huge triggerfish a little distance away. Wow!, I think as I start swimming towards it. It eyes me, turns and charges! Just a mad dash straight at me, mouth open. I was so shocked, all I did was wave my hands and legs and blow a lot of bubbles, but that was enough; it turned at the last second and swam away. Whew.
When I got back to land, nearly the first thing I did after stowing my gear was get out the books and look up that fish. Trigger experts here will already know that it was the Titan Triggerfish.
This monster is huge, up to around 3 feet long, and can be very aggressive, especially during breeding season. The book that I found it in, had a photo with a caption indicating that all three authors of the book had been bitten by this fish. Yes it can draw blood, or leave a bad bruise through a wetsuit. This fish has been known to break the glass of divers' masks. I've personally learned to give them a wide berth, but occasionally have come upon one suddenly, say when coming up over a reef crest, and man, that really increases my air consumption, staying clear of it. There are certain dive destinations that are pretty much off limits at certain times of the year, due to the breeding activities of Titans. I've been diving many places in the world, been in the water with countless sharks including great whites, but nothing I've encountered makes me as nervous as a Titan Triggerfish.
Edit: If this fish had a wallet, it would say Bad M***** F***** on it. His name should be Jules.