Kamala Harris' odds of becoming the Democratic nominee for president surged over fourfold on Tuesday, according to Polymarket, a crypto-based prediction market. Shares betting "Yes" on her nomination rose to 31 cents, indicating a 31% chance, up from 7% earlier. This follows calls from supporters for Harris to step up after President Biden's weak debate performance. Meanwhile, KAMA, a meme coin named after Harris, also saw its price more than double.