The Hog Rider is a Rare card that is unlocked from the Builder's Workshop (Arena 5). He is a quick, building-targeting melee troop with moderately high hitpoints and damage, and able to jump over the river. He appears as a man with brown eyebrows, a beard, a mohawk, and a golden body piercing in his left ear who is riding a hog. A Hog Rider card costs 4 Elixir to deploy.
When he is jumping over the river, he cannot be targeted by any ground attacking units. The Log and Earthquake will fail to damage a Hog Rider while he is jumping. Air troops can still attack him though, and the Inferno Tower and Inferno Dragon will continue to ramp up their damage.
When countering the Hog Rider, using buildings would be your best bet. But be wary, as the offender will usually play around it with cards such as Earthquake. Air swarms such as Minion Horde can also help due to the Hog Rider's usual support cards not countering them.