The opposite of "assuming form of" is to be disoriented and shapeless. When something assumes the form of something else, it means that it takes on a recognizable shape or form. In contrast, when something is shapeless, it lacks any recognizable form or appearance. The antonyms for "assuming form of" can also include words that suggest a lack of intentionality, such as haphazard or accidental. To assume the form of something suggests intentionality and purpose, so the antonyms for this phrase can also include words that suggest a lack of intention or focus.