The title and description gives you lots of room for something creative.
First off exand some ideas on objects or conccepts that appeal to you:
My examples: butterfly, concrete, lightness, grounded, free, flight, feet.. etc
Then work on the title and gravity bit:
My example: Off the ground - leads to in the air, "off the wall", floating, suspended, or maybe even stuck in the ground
a question of gravity... you can go wild with this... you can defy gravity - to challenge the viewers perption - like a floating full size elephant, and a feather weighted down heavity in sand or concrete.
You can also go with a look that is in line with what we percieve as normal gravity
Hope that helps. Best of luck!