The soft mud helped relieve some the pressure from her trotting, while protecting her hooves from collecting anything worse along the journey. Once the mud dried it could trap anything she may have collected and be removed along with the muddy hoof-pies. However, the dirt could also be carrying dangerous bacteria, and other nasty diseases that could infect her hoof alone; resulting in a condition known as 'mud fever'. So it was best to remove any and all dried dirt and debris, and let her hooves air out. Some of the older Stingbush seed pods had spikes twice as long as any needle, which Rarity used to help remove most of the stubborn dirt trapped within the tighter recesses of her hooves. 