Magnetic smart putty! This stuff is insanely cool. what you'll need Liquid starch – We used Sta-flo Liquid Starch. I found it at Kroger, but not at Target or Walmart. Elmer’s glue Iron Oxide powder Disposable bowls for mixing it up – saves washing slime out of dishes! We used craft sticks for stirring. A neodymium (rare earth) magnet – we ordered this set of 10 neodymium disc magnets. A regular magnet is not strong enough. enjoy!