gravity orbs since they can both suck and blow you away based on the engines gravity variable. in devmode you can indeed set them to pull inwards instead of the default push outwards they have in the normal game
Hate to break it to ya, but gravity does not entail repelling other objects. Nice try though. Realism
And they certainly aren't magnets, because how would that repel our non-metal friends...unless they've got metal in them
repelling is simply negative gravity. totally possible in the realm of the unrealistic. and thats indeed how they work.