Have you ever received a gift that you don't want but tried to look appreciative anyway? Pity poor Elon Musk who rushed to Thailand with a tiny submarine, only to be told it was absolutely no use. The billionaire Tesla boss tweeted late Monday saying he'd been to the cave and his mini-sub was "ready if needed." However, it's highly unlikely to be used in the final stage of the operation. The head of the rescue mission, Narongsak Osotthanakorn, previously said "the equipment they brought to help us is not practical with our mission," adding: "Even though their equipment is technologically sophisticated, it doesn’t fit with our mission to go in the cave." Musk said he'd leave the tiny sub in Thailand "in case it may be useful in the future" and added that he was enjoying the country. At least the entrepreneur could be written into a movie on the rescue in the future—Hollywood producers are reportedly already on the scene in Thailand trying to win rights to the story.