Some popular retailers are pulling a kids toy from their shelves.

Amazon, Target and Walmart have voluntarily stopped selling water beads after lawmakers and public health officials called for a ban on the toys.

Water beads are tiny balls made out of extremely absorbent polymer material. When exposed to liquid, they can expand 100 times their initial size and weight, according to the Consumer Product Safety Commission.

Experts say they are a big health risk for kids if ingested.