This was the Fourth labour set by King Eurytheus, it was to capture the Erymanthian Boar. The boar was massive and two times the size of a fully grown adult.
On the way to the boars hideout he stopped by his friends Pholus' and Chiron's caves. Pholus was a Centaur and lived in a Centaurien village. Whilst they were eating together in the cave Hercules asked for wine. Pholus told him that he only had one jar of wine and that it was a present from Dionysus to all the Centaurs but Hercules convinced him to open it. Not knowing it needed to be tempered with wine he became drunk and started to shoot all the centaurs in the village. Due to the fact that the arrows were poisonous (with Hydras blood) the Centaurs died instantly. Suprised that all the centaurs were dying just from one arrow, he picked one up but accidently dropped it on his foot, killing him instantly. The remaining Centaurs retreated to Chiron's cave where one stray arrow had hit him but because he was inmortal he didn't die.
It was mid-winter by the time Chiron told him some advice. The following week he captured the boar.