These Monster Science balls look like candy but are dangerous when ingested by children.

Monster Science and Super Star Science Colossal Water Balls – marble-sized balls that absorb water and grow 400 times their original size – are being recalled because the soft and colorful product can easily be mistaken by kids as candy. When ingested, the toy can expand to cause intestinal obstructions that can be both painful and life-threatening. The toys do not show up on an X-ray and must be surgically removed from the body.

Monster Science packages contain eight balls and “Growth Powder.” Super Star Science! packages contain five balls in an assortment of blue, green, orange, purple, red, yellow or clear colors. They were made in China and just under 16,000 were sold in the U.S. and Canada. For information about refunds, call Be Amazing! Toys (877) 798-9795, from 9 a.m. to 5 p.m. ET Monday through Friday, or online atwww.beamazingtoys.com, clicking on Safety Recall at the bottom of the page.