The infamous "talking horse", favourite for the 2000 Guineas before his debut and beaten at odds-on on each of his first two starts, has been heavily backed for Saturday's John Smiths' Cup at York.
His price was cut from 3-1 favourite in to 9-4 by Coral and from 5-2 in to 2-1 by William Hill.
Coral's spokesman, Simon Clare, said: "Killer Instinct was the only horse the betting public wanted to back this morning but he's been a bookies' friend in the past so we would be insane not to lay these bets."
John Smith's Cup (York, Saturday): Coral: 9-4 Killer Instinct (from 3- 1), 5-1 Pasternak, 6-1 Dee Pee Tee Cee, Siege, 10-1 Mirjan, 12-1 Alboostan, 16-1 Achilles, Captain Scott, Dancing Phantom, Golconda, Raheen, 20-1 others.
William Hill: 2-1 Killer Instinct (5-2), 5-1 Dee Pee Tee Cee (4-1), 11- 2 Pasternak (5-1), 6-1 Siege (7-1), 10-1 Mirjan (9-1), 12-1 Alboostan, 16-1 Golconda, 20-1 others.