There is a big amount of some tokens inside the wallet and you will either be asked to make deposit so as to be able to withdraw the altcoin but that deposit is the wallet owner's target, once a deposit entered the wallet is wired to automatically transfer fund into another wallet address.
Thanks for your explanation, so in the wallet the usdt will be their but their won't be gas fee, so if you import the wallet to your own device, since you think the amount is hug and you will get your own percentage then you will deposit money their which will be use for gas fee, immediately you deposit then automatically bought the money and the gas fee which you deposited will be transferred to another wallet. Waw that's a smart move, we just have to be very careful, I don't really know they are after the gas fee you are depositing.