This is Magic Sand! Also commonly known as Kinetic Sand. The sand sticks together when you are trying to mold them or build any structures like castles. Yet, they can also come apart just like sand when you rub them. Right now Groopdealz has the Easter Fun Magic Sand for only $3.99! (Reg $12.99)
Shipping is $2.99 for the first item and $.99 for each additional.