Surely Justin Gatlin is the nightmare waking IAAF officials in the dead of night.
Two weeks away from the World Championships in Beijing, the prospect of Gatlin (right) out-sprinting Usain Bolt in The Bird's Nest must represent a kind of doomsday scenario for those left flailing so manically against allegations of systemic doping in their sport.
Seb Coe's response to last week's publication of allegations by German broadcaster ARD and The Sunday Times has been one of palpable anger at what he likened to "a declaration of war" on track and field.
True, the allegations did not offer proof of cheating. They simply registered "abnormal" blood readings in a small multiple of major medal winners from the past decade.
But for Coe, the likely next president of the IAAF, to respond with such indignation, suggesting that coverage of the story reflected either "breathtaking ignorance or a level of malevolence" did not sound an especially hopeful tune.
Now next up Gatlin, twice busted for doping, goes for gold in China. Expect Coe and friends to watch between the gaps in their fingers.