Hi I own 2 of these (but have had up to 4 at a time). Let the frog be, he'll snap out of it. How warm is the tank? Is the substrate damp and does he have a water source? My 2 Grays hunker down in the soil at times too but mostly it's because 1. no food and 2. looking for water and the substrate is damp. These frogs need it to be 80-85 degrees