This is a giant stone jaguar that has crystal eyes. It is sent by Tzekel-Kan to disrupt the Year of the Jaguar festival. It doesn't speak at all. This beast was first depicted in Tzekel-Kan's tome. The process to activate it is mostly unknown, the only known ingredient being a human body, which was provided in the form of Tzekel-Kan's servant. Through this monster, Tzekel-Kan was able to cause significant damage to El Dorado, as well as almost causing Tulio and Miguel to fall into the whirlpool.
The giant jaguar is immune to the spears of the Aztec warriors. It also appears to be unaffected by lava, charging out of the lava without being melted or slowed for more than a moment.
As this beast is controlled by Tzekel-Kan, it is possible that attacking Tzekel-Kan would inactivate the jaguar or cause it to become uncontrollable. It is confirmed that damaging the jaguar will cause Tzekel-Kan's focus to waver, as the mad Aztec priest needed a moment to recover after the jaguar's left eye was broken by Altivo. The whirlpool presumably leading to Xibalba ended up destroying it, meaning that while the beast is sturdy, it is far from invulnerable.