Kids' toys that make goo aren't new, but the Discovery Polymer Lab takes that age-old tradition to its nerdy conclusion, teaching kids about long chain molecules and the physics of slime. Ingredients are included to make distinct slime, ooze, and foam from water and powder. Plus it's got the Kid Frankenstein mad scientist look down pat. (Or perhaps less gothic than jet aged. Maybe "Young Rusty Venture, Boy Scientist"?)
It's $40 from the Discovery Store, plus shipping.