Magical forests are never a good place to sleep, especially seeing as much of the population is nocturnal. Firewood taken from the wrong tree can turn against its collectors, and a strangling onslaught of angry twigs and branches can be surprisingly severe and difficult to disentangle yourself from. Fires themselves attract enemies, and not only malevolent predators. Giant moths and gloomwings are tempted by the heat and light, but are often misunderstood.
If a creature is transformed into another creature (say, a human into a dog), then that creature will become more and more accustomed to the new form until a point is reached where reversing the spell is impossible. A second transformation is possible, but the creature will have to go through the whole process again.