Curse of depression

Enchanted creature lose all its abilities.
When enchanted creature is dealt dammage,
it becomes a green wolf with base power and thoughness 2/2. If it it is a wolf, it becomes a
black rat with base power and toughness 1/1.
If it is a rat, it becomes a blue frog
with base power and toughness 0/1. If it is a frog, destroy enchanted creature. Its controller lose
three life.