The SPCA has warned against people who find injured animals taking matters into their own hands.
It comes after a popular Facebook page mourned the death of a possum, the man behind it claiming he bashed the suffering creature to death.
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Asher Ramsey of the page Waikato Admins told Newshub the country suffered a "tragic loss" after he discovered the possum, which he named Rosko, in a state of distress on Wednesday.
"Rosko was discovered injured... and unable to use his rear legs and sadly had to be put down," he told Newshub. "He will be remembered by our small community and has touched the hearts of many Kiwis."
Mr Asher said he put the possum down himself using a cherry wood branch, saying it was one of the hardest things he has ever had to do.
"He was very loyal and followed me around my work day dragging himself around with his front paws… Many people feel the loss of the little guy. He's now very popular and I feel it's only right he leaves a legacy."
But the SPCA said people need to get in touch with an expert if they find any injured wild animals, rather than take matters into their own hands.
"While it's understandable that someone would want to end the suffering of a severely injured animal, this must be done humanely to prevent further suffering," a spokesperson said.
"Humane options could include humane euthanasia by vet or an appropriate humane shooting by an experienced person.
"The most humane option will differ in each individual situation depending on the injuries, animal and its location, so seeking professional advice is best.
"It's also important to note that an injured wild animal could be unpredictable and put you at risk, so please consider your own safety."
It wasn't clear where Rosko was found.
Heartbroken fans of the possum shared their grief on the Waikato Admins page, with several pictures of the possum with added angel wings cropping up.
One picture included a group of other deceased celebrities, including gorilla Harambe, Steve Irwin and Muhammad Ali.
Some of the page's 25,000 fans shared their desire to see him once more.
"I'm so sad, I just want Rosko back," one person said.
"Why [the f**k] am I crying in my car [right now]," another wrote.
Some people have lashed out at the page owner in their grief after a meme thought to be in poor taste was shared. The image showed a poorly photoshopped picture of Rosko in front of a nail gun with the caption "I'm so sorry Rosko."
"I think this is very disrespectful," one person responded, receiving three 'sad' reactions.