Pony Painting Parties have become a trend for children's parties across the UK - but the practice has sparked outrage on social media and petitions have been set up to ban it.
Children use products, which are primarily water and chalk-based to paint designs onto ponies from writing their names, or putting handprints on them, to covering them with hearts and stars with glitter which is biodegradable and edible.
Those behind such parties reckon it's harmless fun and the painting is often done as therapy, helping children at centres offering riding for disabled people.
But not everyone is happy with the idea. While campaigners are petitioning to get what they describe as the 'disturbing trend' banned, animal rights group People for the Ethical Treatment of Animals, or PETA UK, says parents need to be reminded that ponies and horses 'aren't party props'.
Experts on horse welfare are divided on the issue.
Lucy Grieve from the British Equine Veterinary Association says that vets use chalk to mark areas of horses' bodies and learn about their anatomy. She says "as long as the paints don't cause any harm to the animal, there doesn't seem to be any cause for concern."