The Pirate Grotto is a Battle Arena unlocked with the Pirate Seas Adventure Pack. This arena is circular with a main ground level, higher stone level, and a sunken pier. Pirate Grotto has five Bounce Pads and two Teleporters. The Teleporters send the Skylanders to the north of the map, next to one of the Hazard Activators.
There are two Hazard Activators in this arena. Once triggered, a naval bombardment begins. Skylanders should watch for yellow crosshairs on the ground level and stay out of the way of incoming fire.
↑From page 13 of BRADYGAMES' official strategy guide for Skylanders Spyro's Adventure.