Gravity is a Legendary natural-type fruit in Blox Fruits. It is expensive and hard to obtain Gravity fruit. It costs $2,500,000 or 2300 Robux and has a 1.7% chance of being in stock, so it will take some time to show up in a shop. It has a spawning chance of 1.59%, so there is a low chance that you will find it while playing.
Gravity is not that great fruit when you compare the price and value that you will get. It is better to get some other fruits that are much cheaper and will give you better value. It has decent damage, a lot of stuns, and range skills, which makes it good for farming and raids. The problem with this fruit is its cost, and it is relatively bad for PVP. So if you get it, it is best to trade it away.
What combo you will use depends on your in-game situation, who you are fighting with, and what you want to achieve. It is best to spend some time testing all possible combos, and by doing that, you will learn how to use what works best for you and also how to counter it. So go and test Gravity in a game.