Undersea Adventure is a 58-piece MAGNA-TILES set with an ocean theme. Besides an XL baseplate and the quarter domes and arcs used to build pod-shaped structures, it adds straight and curved slides, trapdoor tiles, new Sensory Tiles, soft coral and octopus-tentacle pieces, arch windows and decorated ocean tiles. Two diver figures and four sea creatures (a dolphin, a shark, a sea turtle and an octopus) turn each build into a scene for storytelling. The pieces connect magnetically, so kids can pull a build apart and try a new layout.