Researchers studying how pain works have discovered an antidote to the deadly sting delivered by the most venomous creature on Earth — the Australian box jellyfish. A single sting to a human causes necrosis of the skin, excruciating pain and, if the dose of venom is large enough, cardiac arrest and death within minutes. The new antidote, discovered using CRISPR genome editing techniques, blocks the symptoms within 15 minutes after contact.