Tang Dynasty depiction of Vajrapani

Hercules

Greco-Buddhist statue of Vajrapani (left) and Buddhist monks

The Buddha and Vajrapani (right).
The deity's club was changed to a staff sometime after Buddhism entered China. He was later worshiped as the de facto guardian deity of the Shaolin Monastery. One legend set during the Red Turban Rebellion in the Yuan Dynasty states the rebells were besieging the monastery when a lowly kitchen worker threw himself into an oven and emerged a mountain-striding giant wielding a long fire poker as a makeshift staff. After he had defeated the rebells, all of the other monks realized that it was none other than Narayana (one of the his Chinese names). Thus, he was also worshiped as the progenitor of the famous Shaolin staff method. (It's important to note that Bodhidharma was not associated with Shaolin arts until 1629, when the Sinew Changing Classic was written by a Taoist.)
A Shaolin stele portraying Vajrapani in his Narayana form (Image is slow to load. Sometimes it does not load at all.)

Another legend says that devotees could gain supernatural strength and boxing abilities if they prayed to him most ardently. However, this strength could only be achieved by him 'force-feeding' the vegetarian monk raw meat. This legend is the root of all “meat-eating martial monks”.
Did you notice how in all the statues of Vajra and Herc, besides the club and bare chest, one of the central motifs seemed to be him shifting his weight onto one leg? Look at them again.
If statues of Hercules truthfully influenced Vajra's look, then Herc indirectly influenced Shaolin lore. Another interesting thing is that the Spartans believed themselves to be descendants of Hercules. So, the Greco-Buddhist art has a connection to both the Spartans and Shaolin warrior monks.
