A bush can become material
The first checked Druid room pairs transmutation with the Thief’s pull. A bush occupying the western plate can preserve access while the heroes work around the long hedge corridor. Transformations can be reversed; the timing matters because bushes and movable blocks offer different routes.
Combine the transformation with a push
The next room pairs the Druid with the Warrior. Three blocks made from the hedge are pushed into a high row of plates, opening the eastern goal chamber. These two examples do not establish a complete transformation table for monsters, all heroes or the full release.