A totem most likely dedicated to the bat loa on the Echo Isles
Hir'eek, the Bat, is one of the Primal Jungle Gods in the troll pantheon.
He is represented on Azeroth through a Champion of his choosing, a position once held by the deceased High Priestess Jeklik.
Adventurers are guided by the spirit of Hir'eek in  Backdoor Dealings, where he takes the form of a shadowy gargoyle.
Shortly after the events of Landfall, Hir'eek communicated with Vol'jin, betrayed by Garrosh Hellscream, through visions. 
This article or section includes speculation, observations or opinions possibly supported by lore or by Blizzard officials. It should not be taken as representing official lore.
It is very likely that Hir'eek is the reason Darkspear troll druids transform into bats, like how its fellow Gurubashi Loa Shirvallah gave them the ability to transform into tigers.