A very astute child watched a tarantula hawk wasp attack a tarantula—and narrated the science behind the encounter beautifully for his family, who was watching it unfold live with him.

The wasp, which is parasitic, was attacking the tarantula in the Sonoran Desert in Arizona. The insect’s goal was to try to paralyze the spider, as the child suspected. Karen and Matthew Perry from Tucson, Arizona, captured the footage with their children, Cash and Cadence, while on their way to go hiking.

As the attack took place, Matthew Perry was unsure of whether the spider was defending itself or had been “nailed,” as he says in the video.

Cash, the child who helps narrate what is happening, was able to identify what kind of wasp was involved.

“Why is she acting like that?” Matthew asks about the spider.

“Taunting,” Cash responds. “If it’s been stung it would be completely still.”

The wasp continues to sting the spider several times throughout the video. Once the spider is paralyzed enough from the insect’s venom, the wasp will lay a single egg inside the subdued tarantula’s belly. That sets off a chain of biological events that turn the spider into a sort of zombie. (Learn more about nature’s zombies from National Geographic magazine.)

The wasp will drag the weakened but alive spider back to the arachnid’s own nest. When the wasp egg hatches, the larva will eat the spider—still alive but paralyzed—from the inside out. The larva avoids vital organs at first, to keep the spider alive for as long as possible.

The spider can put up no resistance as it is being eaten from the inside out. The process can take several weeks.

As the family in the video continue to watch the wasp work on the spider, they can be heard gasping with disbelief at times. Karen Perry said it was crazy and sad to watch.

“It’s nature,” says Matthew Perry. Cash adds: “This is what happens.”