Runescape Slayer Creatures: Mogres

Once you're at 32 Slayer and do the Mogre activity, you can hunt down Mogres. You'll need fishing explosive or the shaker of explosive to attract them.
Use the fairy rings or just run south from Port Sarim until you can't anymore, and you'll be there.
Other than raw fish, there are some cosmetic pieces they drop rarely, but that's pretty much it. Not a lot to really do here.