The arrows pierced and tore through the purple cap mushrooms much faster than Walker was able to freeze them. Luckily there was water still in puddles around the ground due to the shade of the forest keeping the partly cloudy sunlight from drying them up. While he let another newly created frost whip fly out to land on two of the purple cap mushrooms bodies, Walker channeled his mana to draw in even more of the water elemental mana around.
The water reacted and started to freeze on the ground. His mana was being used up much faster than he expected but he knew that he had enough to do what he was trying for. Thankfully the area was devoid of other plants due to the purple slimes moving through so his use of water magic would not harm the forest.