There's the famous case of a guy doing that to a bank in Russia and winning, so it's not unheard of.
In this case Disney offered a contract that you enter into via tweeting a reply. If you send back modified terms then Disney has the chance to review the new contract and reject or accept it. If a human saw your tweet and still included it in whatever marketing materials they are creating then you might have a good case.
Just as Disney would need to argue that you knew you were being bound by their ToS when you tweeted them, you need to show they accepted your terms. The part of your example about a time limit wouldn't fly for that reason. Both sides also have to think the contract is reasonable (not a joke). If you put a bajillion dollars as the price, there's no contract. I'm not sure if $100k for a tweet is believable.
In this case Disney offered a contract that you enter into via tweeting a reply. If you send back modified terms then Disney has the chance to review the new contract and reject or accept it. If a human saw your tweet and still included it in whatever marketing materials they are creating then you might have a good case.
Just as Disney would need to argue that you knew you were being bound by their ToS when you tweeted them, you need to show they accepted your terms. The part of your example about a time limit wouldn't fly for that reason. Both sides also have to think the contract is reasonable (not a joke). If you put a bajillion dollars as the price, there's no contract. I'm not sure if $100k for a tweet is believable.