The Falls of the Hounds is a massive waterfall that lies along the route of Blaine the Mono, between the cities of Rilea and Dasherville. They are much larger than Niagara Falls. The waterfall gets its name from the rock formation in the middle of it, which resembles two dog heads.
The dog heads would absorb the energy of the beam and shoot lightning like electricity from their eyes and into Blaine so he could recharge his battery.
It's hinted that the technology could've been made by a civilisation predating the Old Ones.