Dogecoin, a cryptocurrency inspired by a "doge" meme, surged 25% on Wednesday after a single-word tweet from Elon Musk. Tesla CEO shared a picture of the meme-famous Shiba Inu in a space suit, planting a flag on the moon and tweeted, "Literally." Earlier this month, Dogecoin jumped after Musk said he bought some of the cryptocurrency for his nine-month-old son.