This cute little playpen for kids is an inflatable castle style space that includes 20 soft, flexible toy balls. The shallow pit is surrounded by four vertical inflated posts. There are rounded arches with decorated enclosure panels on two sides and straight support arches on the other two open sides.
This darling playset is designed for kids aged 2 and older, but reviews indicate younger children enjoy it, too. The pit itself can hold more than the included 20 balls so you might want to purchase extra along with this playset for your young Frozen fan. A set like this 100 Pack of Blue & Transparent Ball Pit Balls might work.