Barrel of Monkeys is a game featuring small toy monkeys with arms that extend and curve like hooks. A player picks up a monkey by an arm, then uses the other arm to hook a second monkey. The player’s turn continues by hooking more and more monkeys until a monkey is dropped, then it’s the next player’s turn.

Leonard Marks, the toy’s creator, came up with the idea while he was selling greeting cards in 1961. While waiting to talk to shop owner Robert Gilbert, Marks started playing with snow tire replacement chain links. He was so entertained that he told Gilbert that it could be turned into a fun toy. Gilbert put Marks in touch with Milton Dinhofer, a toy creator who made the first wearable toy space helmet and the Sip-n-See (the first twisted plastic straw).

When they met, Marks brought S-shaped hooks and Dinhofer pictured turning them into monkeys with hooked arms. They formed a partnership with Dinhofer designing the toys and Marks selling them. They packaged 12 monkeys together in yellow, green, and red colors, and called the game Chimp to Chimp. The monkeys were intentionally made to be small enough for kids as young as three years old to hook all 12 without needing to stand on a stool.

Woolworth was the only store that agreed to carry Chimp to Chimp, but stipulated that Marks and Dinhofer had to provide 13 weeks of TV advertising. The toy makers could not afford to pay for it, so in 1964, they partnered with Herman Kesler to help find a home for the toys.

Kesler met with Lakeside Toys’ CEO and President Zelman Levine and other executives to show them the toy. The demonstration was a big success, Levine approved it and took samples to their headquarters in Minneapolis. They renamed the game Barrel of Monkeys and released it in 1965 with Marks, Dinhofer, and Kesler receiving ongoing royalties for their creation.

Barrel of Monkeys has changed hands several times over the years from Lakeside Toys to Leisure Dynamics to Coleco Industries, and finally Hasbro. Not only has it been popular as a game, Barrel of Monkeys has also been featured elsewhere in pop culture. The characters appeared in the Toy Story film series, the 12 Monkeys movie borrowed their style for the movie logo, and Tony Stark referenced the game in Iron Man 3.