He hears an odd pulsing sound attracting him

He continued in this way for another indeterminable stretch of time before he began to notice a rhythmic thumping sound that he hadn’t heard before outside of his own footsteps and the hum of the forest.

He didn’t stop walking entirely but he slowed his pace down to get a feel for where it was coming from.

There.

It sounded like it was coming a few degrees to the left, a bit away from the main path.