Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
In a Mexican town a large banner advertises a "Great Toad and Chameleon Circus." Another sign reads "Today - The Conquest of Mexico." We see on a platform a large replica of an Aztec city with pyramids and dozens of horned lizards (probably Mexican plateau Horned Lizards) some very large and fat, a few smaller, all tied up at various places in the city, including on pyramid steps and on the tops of the pyramids. Most of them are dressed up in brightly colored hats and outfits to look like Aztec royalty. Three large Spanish Galleons that are full of Giant Toads dressed up in silver armor like Spanish soldiers or in brown robes and hoods like Spanish monks are wheeled up to the platform. The toads are put on the Aztec city where they begin to hop over the horned lizards. We see some of them attempting to bite the horned lizards. Then we see bright red paint representing blood flowing down from the tops of the pyramids onto the lizards and toads. In a wide shot we see live toads and lizards piled on top of pyramids, along with dead ones hanging over the edge, all covered with red spaint. Then the pyramids begin to explode. We see several explosions with toads and lizards and body parts flying out. These look likereal animals being killed. They could be fake rubber ones, but it's not likely on a lowbudget movie like this. After the carnage is over we see piles of dead animals and a few live toads hopping off the platform. The director Alejandro Jodorowsky wanted to convey something about the brutality of the conquistadors and the church and their bloody conquest of Mexico and Native Americans but what I take away is that he thinks it's ok to abuse and kill animals for his art. He constantly pushes the limits in his films, challenging us with views of violence and insanity and evil, but in this scene, and in the vicious dog figh later in the film, he goes too far.
You can watch the carnage on YouTube.