At first glance, this looks like a cross between a hearing aid and a Derringer pistol, but it's actually something that belongs on the desktop. The Sigma SGM2 mouse owes its funky design to the intended use as a presentation device, to control the computer screen pistol-style with thumb and trigger finger.
It sounds like a grand idea, and we might even be able to get past the weird look of this mouse if it weren't for one thing: It's not wireless. Which, as Newlaunches correctly points out, makes it far less appealing for standup lectures or other presentations where you would need to avoid tripping over the cord. However, if you encounter hecklers in the audience, you could always threaten to shoot them.