The Jumping Shark can travel above water at 50 mph and under it at 25 mph. It can leap up to 16 feet in the air, and -- as if you even had to ask -- of course it can do a barrel roll! Ninety percent of villainy is in the presentation, and when you "present" this baby at your next caper, you can bet the water around Aquaman will suddenly get a little bit warmer:

Innespace Marine
Nose-mounted machine guns sold separately.

Was this vehicle designed specifically for supervillains? We don't know: Can you get a Prius in bloody cyborg-animal print?

But you don't have to choose between shark-induced terror and performance: The Seabreacher comes equipped with a vector thrust system for optimal maneuverability, a snorkel cam on the dorsal fin that lets you see the surface while submerged (partially so you're not steering blind, but mostly so you don't miss a second of the shock, terror and regret on your enemy's faces) and even a stereo system with a docking station for your iPod. We recommend something suitably nefarious, like "Ride of the Valkyries," but the thing is pretty soundproof; nobody's gonna judge if you cry havoc and let loose the dogs of war to some Katy Perry.

Innespace Marine
Nothing we have ever done is as fun as that looks.

You're going to need superior firepower if you ever want to shut up that damn mermaid and her stupid racist caricature crab friend, and an Uzi covered in Saran Wrap just isn't cutting it. Enter the APS Underwater Machine Gun. The APS (Aquatic People Slayer?) fires 4.75-inch nail-like bullets at a rate of about 500 rounds per minute.

Maxim Popenker
If those were wooden nails you'd have the perfect vampire defense weapon.

It's capable of more distance and penetration than anything else out there, just like the writers of a certain comedy website (ladies). The underwater range extends well beyond line of sight even in the best visibility, which is a remarkable feat, considering that most firearms don't work underwater at all, and if they do, only for extremely short distances.

Ria.ru
"We'll see who's laughing now, dolphins."

But you don't want to be the lame-ass villain with the officially sanctioned hardware, and if the APS is so awesome, surely it's already in use by Navy SEALs or something, right? Nope. The SEALs use the German-made HK P11. In fact, even the Russians (who invented the damn thing) don't really use the APS: It's heavy, bulky and hard to swim with, and firing it above water turns your accuracy to crap and screws up the barrel really fast. Aquatic gun battles simply aren't a priority for most militaries, so though it was first engineered by an official branch of Russia's armed forces, it was too impractical to see much application anywhere. In other words: It's a military-developed, submersible, nail flinging hand cannon deemed too impractical, unsafe or altogether insane for official use. Nobody could ask for a more appropriate supervillain weapon, and if they do, why, you can simply shoot 500 goddamn nails into their chest.

REMOV
Now that we know this thing exists, we can never be happy until we own one.

We're not just throwing adjectives around, either: They really are unpredictable. This device gives you no control over the sharks; it doesn't render them docile or stun them in any way. In fact, because the frequency is imitating distressed fish, all the sharks show up hungry and ready to feed. It's basically a dinner bell that mindless eating machines of the sea can hear from miles away. This is a device practically custom-built to call schools of hungry super-predators to beaches full of splashing, unsuspecting swimmers. So wait, who are they selling this to again? What's their chief demographic, Nega-Aquamen?

Aquaman #31, Shark Bait
Well, that's one sale at least.

Hey, just because the hero uses it, that doesn't mean the villain can't, too. If anything, there's a kind of poetic cruelty to using his own precious gadgets against him, or just to inflict general malaise and suffering.

Cops after you? Not a problem when your car is a submarine; just take that bank heist under the sea. Navy harassing you again? Let's see a destroyer follow your aquatic rampage into midtown, baby. The sQuba is the perfect car for crimes bridging both worlds, a high-speed, guaranteed escape, or just lazily giving the finger to any do-gooder who's less than completely amphibious.

Rinspeed
There's no way Q's name isn't somewhere on the patent for this thing.

There's even a portable backpack "Ghostbuster" model for individual use: It only delivers 200 volts, but it looks just like a metal detector, so you'll really be able to get right up on that target without arousing suspicion.

Getty
"Oh, don't mind me, just looking for boring old coins and A-HA! MOCK THE PHANTOM RAY, WILL YOU?!"