Ok, here's a question for you sciency-nerds: not too long ago in the new Legion comic, there's a very amusing moment where Brainiac 5 insults Star Boy (who controls gravity to make things more heavy) and Light Lass (who controls gravity to make things more light), basically mocking them for the fact that they control, between the two of them, one of the "most powerful fundamental forces of the universe" but they can't think of anything more clever to with their powers than pin down or unbalance their opponents with it.

It cracked me up because it was such a total B5 thing to say, but at the same time it got me wondering: let's say you have a superhero, who's power is to control gravity, being able to make objects have increased or decreased gravity.  What exactly COULD such a character do, other than immobilize dudes?

RPGPundit

Defensively, altering the Gravity significantly either direction between two points would make any sort of ballistic accuracy impossible.   Increasing the gravity near most modern engineering projects (bridges, skyscrapers, etc) by even realatively trivial amounts would tend to bring things crashing down...

Depending on the power and control, one could presumably use gravity powers to tear apart molecules and even force the transsubstantiation of elemental matter...

Of course, in industry either power could be a serious money maker in terms of working with exotic materials, assisting scientific expirements involving mass colliders etc.  Obviously Light Lass could make VERY good money reducing Escape Velocity for hauling loads into space... given the cost per pound in energy to acheive that, paying her millions per launch would still save her employers a fortune.

Quote from: RPGPundit;280883It cracked me up because it was such a total B5 thing to say, but at the same time it got me wondering: let's say you have a superhero, who's power is to control gravity, being able to make objects have increased or decreased gravity.  What exactly COULD such a character do, other than immobilize dudes?

As an aside, among superheroes, the ability only to increase or decrease a force isn't usually a main ability.  i.e. A superhero with power over fire can do more than just make existing fires bigger or smaller -- they can at the very least move them around, if not create them.  

Sticking to the stated limitation, though, a few ideas:

1) Manipulating weather, in particular a huge burst of air pulled down that would rush out from a chosen spot.  
2) Create gravity waves by cycling gravity force very quickly to create powerful vibrations to shake things apart.  
3) Smacking people around by putting things above them, and then smacking them with superweight force.  i.e. Overhand swing with a weapon, say.
4) Kicking people into the next state: Turn someone super-light, and then kick them to send them sailing away in a giant arc.  They wouldn't be going very fast because of momentum, but it could take them a long time to come down.  
5) A combination of 3 and 4 for bombardment: throw a safe or two a mile, and then when it is over where you want to hit, have it come crashing down like a hundred tons of bricks.

You could also make certain spots in your body heavy or light, and make them quit functioning... like super light gravity around the atriums of the heart, or super dense along the decending colon.

I'm not sure what all that would do, but I'm sure it wouldn't be healthy.

There are a lot of things. You could influence light and magnetism, if your control is strong enough you might be able to bend light around you to be invisible (or at the least blur your image.)  You can influence the weather as mentioned. You could control and shift where the particles that create the auroras on earth come out--which means you might be able to irradiate people on a similar planet. You can induce veritigo by minute and sudden shifts within the ears of a target. You can prevent materials from exploding do to excessive pressure.  You could bend bullets around your body, or better yet use your abilities to fire projectiles of your own, even around corners. You could negate gravity in such a way to create a dust storm then drop super gravity on set dust to slash open vehicles, or impede projectiles (Needs careful superhuman timing.) You could make a fortune allowing people to launch satellites whose mass you reduce. You could even work on your own vehicle to exit the atmosphere of earth.  You can probably influence atomic interactions as well, the exact nature would require advanced physics but I suspect you could suddenly stop say neutrinos at a spot. All that expended energy from them hitting a gravity wall has to go SOMEWHERE.

By shifting your own gravity you could run or move on any surface--water, clouds, walls, ceilings. You can also interrupt others movements by forcing two (or more) gravitic forces on them causing them to weave and stumble. You could mimic super strength readily. The genre differs from real physics but I imagine if you played even looser with it, you could open portals (micro singularities or such) and protect materials passing into or out of them--more akin to making a portable hole than a teleportation or gateway  Increase the gravity over a specific spot and create knife like blades of air...and so on.

These are all some great ideas guys, thanks.

RPGPundit

http://www.marveldirectory.com/individuals/g/graviton.htm

This character from Marvel gives a decent idea what kind of things can be done with control over gravity.

Crush your enemies into a singularity? Propel yourself or a spaceship through space near the speed of light (or FTL depending on which universes physics you use).