Context. Feral cats are invasive predators of small and medium-sized fauna throughout Australia. The only broad-scale population-management technique for feral cats currently available in Australia is poison baiting. As poison baits for feral cats must be surface-laid, this can lead to the unintended exposure of non-target species consuming the baits. Encapsulation of a toxin within a robust, controlled-release pellet implanted within the meat lure (the combination of which is termed the Curiosity (R) bait) substantially reduces the potential risk to non-target species. Paraaminopropiophenone (PAPP) has been shown to be an effective toxin to which cats are highly susceptible. Aims. The present study aimed to measure the efficacy of encapsulating PAPP toxin in a controlled-release pellet on feral cats in a pen situation and to document the observed behaviours through the toxication process. Methods. Pen trials with captive cats were undertaken to document efficacy of encapsulating PAPP toxin in a controlled-release pellet and to assess the behaviours during toxicosis. These behaviours inform an assessment of the humaneness associated with the Curiosity bait using a published relative humaneness model. Key results. The trials demonstrated a 95% consumption of the toxic pellet and observed the pattern of behaviours exhibited during the intoxication process. There was a definitive delay in the onset of clinical signs and death followed at,185 min after the first definitive sign. The humaneness using the relative humanenessmodel was scored at `mild suffering'. Conclusions. The encapsulating PAPP toxin in a controlled-release pellet for feral cats is effective. The feral cats display a range of behaviours through the toxication process, and these have been interpreted as mild suffering under the relative humaneness model. Implications. The documented efficacy and behaviours of encapsulating PAPP toxin in a controlled-release pellet provides knowledge of how the PAPP toxin works on feral cats, which may assist in decision-making processes for conservation land managers controlling feral cats and whether to incorporate the use of the Curiosity (R) bait into existing management techniques.