Threshold Guardian
The Eternal City, oil on composition board, 1934-37, Peter Blume, Museum of Modern Art. Blume worked on this painting for three years. The green jack-in-the-box figure was modeled after Mussolini who is shown emerging from the Coliseum.
When you attempt to reach a new level of knowledge, self-awareness, empowerment, creativity and freedom from past enslavements, addictions and entanglements, you are very likely to encounter threshold guardians, which may take the form of sabotaging characters (within or without) or other adversaries and adversities that test your will, perseverance, and worthiness to advance to the next level.

I have often encountered threshold guardians at the start of a valuable journey or life change. I used to regard these encounters as setbacks or hardships, but now I am often able to recognize threshold guardians as signs that I am on the right track.

When threshold guardians appear it is a sign that there is treasure beyond the threshold. Summon your will to keep following the path with heart.
See Threshold Guardians for a discussion of this archetype and examples from popular culture and classical myths