Few movies tap into my millennial nostalgia quite like Robert Rodriguez’s 2001 classic, Spy Kids, but those Thumb-Thumbs are pure nightmare fuel. With its badᴀss Cortez family, thrilling action sequences, and even a very young Glen Powell in a minor Spy Kids 3 role, the franchise has it all. Starting with 2001’s Spy Kids, the movie series has been hugely successful, thus far consisting of five feature films. Rodriguez confirmed that there are likely more Spy Kids films to come, developed by Netflix, who also released the franchise’s animated series, Spy Kids: Mission Critical​​​​​​.

As I got older, I fell away from the Spy Kids franchise (the best movies are the ones with the entire Cortez family, anyway). I fancied myself a burgeoning cinephile, eager to consume R-rated ’90s movies I was too young to have seen in cinemas. These included Pulp Fiction, Fight Club, and, of course, From Dusk Till Dawn, which introduced me to Robert Rodriguez for what I thought was the first time. So, imagine my surprise when I learned that the director of the hyperviolent Planet Terror and Sin City actually helmed my favorite childhood movie. And then those creepy Thumb-Thumbs all made sense…

Spy Kids’ Terrifying Thumb-Thumbs Explained

Their “All-Thumbs” Appearance Is Incredibly Frightening

In the original Spy Kids movie, the Thumb-Thumbs are introduced as Fegan Floop’s robot henchmen. If not sophisticated, their name is definitely apt, as the Thumb-Thumbs have giant thumbs for hands, legs, and a head. We first meet them when they capture Gregorio and Ingrid Cortez, who are on their mission to stop Floop, and they take the agents back to Floop’s castle. While I certainly found the Thumb-Thumbs to be grotesque, I wasn’t rightly and properly terrified until the home invasion scene, when a group of ninja Thumb-Thumbs descend upon the Cortez house, and kidnap Felix.

The idea of anything attacking your home is beyond scary, especially to a kid, but something as horrifying-looking as the Thumb-Thumbs sent me over the edge. Even if they looked like regular robots, they’d be less frightening, but their makeup of what looks like oversized human thumbs just sent a shiver down my spine. For me, it didn’t matter that the point of their “all thumbs” appearance was that they were bumbling and clumsy. Heck, I could barely even watch when the Cortezes were given a docile Thumb-Thumb as a waiter — the damage was done.

Robert Rodriguez Invented Thumb-Thumbs When He Was 16 Years Old

He Won An Art Contest For His Drawing Of Them

Given my unadulterated fear of the Thumb-Thumbs, I had to wonder how Robert Rodriguez dreamed up such a bizarre creation, and the answer is kind of… sweet. It turns out that they were born out of a hangup Rodriguez had as a 16-year-old artist. Rodriguez revealed to Decider, “I was so bad at drawing hands, that I was just drawing my thumb. When I drew it, it looked like a head.“

The future film director then gave the thumb-head more thumbs for limbs, drew him a soccer uniform and an eyeball for a soccer ball, with the caption, “Thumb-Thumbs playing eyeball.” But that’s not the most hilarious part. Rodriguez revealed,

“I won an art contest with it.“

So, the Spy Kids director ultimately wasn’t trying to give us millennials nightmares after all — he was just inspired by his own teenage drawings and decided to put them in a movie. Knowing this fascinating information made me decide to go back and rewatch Spy Kids to appreciate Rodriguez’s Thumb-Thumbs creatures more. And you know what? They’re still terrifying.