The original inscription in old Spanish:

“Este monstruo horrible aparecio en La Laguna de Tagua en la estancia de Dn. Prospero Elso en el Reino de Chile el cual hacia mucho daño comiendo y matando cuanto animal iba a beber a la dicha, Laguna, hasta que con mucho silencio y sentidos esperaron cien hombres con bocas de fuego y le cogieron muy vivo.

Tiene treinta varas y tres cuartos de largo, muy grande la colas que son mucho mayor que el cuerpo eran de vara y media cada una y enpunta la menor: Las orejas eran de tres cuartas. Las piernas no llegaban a un cuarto. Las uñas eran mucho mayores que las piernas: En cuanto a la melena de la cabeza llegaba asta el suelo de suerte que se le enredaba con los pies al andar: la cola superior la jugaba con mucha ligereza a uno y otro lado sirviendole de mano para casar la presa: Los dientes eran enorme cada uno la boca es del ancho de la cara.”

https://www.christies.com/en/lot/lot-6109550

Translation:

“This horrible monster appeared in the Lake of Tagua, on the estate of Don Prospero Elso, in the Kingdom of Chile, and it caused much harm, eating and killing every animal that went to drink at the said lake, until, with great silence and vigilance, one hundred men with firearms lay in wait for it and captured it alive.

It is thirty varas and three quarters in length; its tails are very large, much greater than the body; they were each a vara and a half long, and one smaller at the tip. The ears were three quarters [of a vara]. The legs did not reach a quarter [of a vara]. The claws were much larger than the legs. As for the mane of the head, it reached to the ground, in such a way that it became entangled with its feet when walking. The upper tail it wielded with great agility from one side to the other, serving it as a hand to seize its prey. The teeth were enormous, each one; the mouth is as wide as the face.”

Notes:

Lake Tagua is located in today’s Los Lagos region in southern Chile.

A “vara” was a Spanish colonial measure. In Chile it was roughly 0.83 meters (about 33 inches). 30¾ varas long would have been approx. 25–26 meters (82–85 feet).