The secruyu is a lizard and communicates as such.

The secruyu is a plain little lizard, generally grayish-green or grayish-brown.

The secruyu is native to western Amol-Kalit, in the vicinity of the Forbidden City and the foothills of the Seret Mountains.

The secruyu's venom is a paralytic strong enough to kill or paralyze a human or cripple a camel. Not coincidentally, the secruyu's favourite prey is nearly anything larger than itself.

The venom is unstable and prone to losing its potency. (For example, a bite from an undead secruyu will partially paralyze a human, but no more. Extreme heat, like a high fever, will break down even full-power venom quickly.) Apothecaries can stabilize the venom at full potency in pure alcohol. Some assassins are known to daub their blades or darts with it, letting them partially or wholly paralyze their target with a shallow injury.

The secruyu was well understood long ago, when the Forbidden City was inhabited. Never an especially common species, it has largely faded from public awareness.

Plenty of tall tales involve paralysis taking hold of unwary visitors to the Forbidden City, who may wake up with something chewing its way inside them. Whether the stories associate that risk with a lizard, as opposed to a snake or scorpion or ghost, is a matter of chance. One common story involves an explorer who escaped the ruins, only to be killed when a brood of secruyu ate their way out of his camel.

Some apothecaries and assassins in Amol-Kalit know the uses of secruyu venom. It's not necessarily a secret, just rare.

The Burning of Elbion - a necromancer uses an undead secruyu as a weapon.
Play the Hand of Fate - a small bottle of stabilized secruyu venom is a wager in a high-stakes card game.