Your dream appears to be rich in symbolism and could reflect various aspects of your life and subconscious. Let's break it down:

1. The Green Witch (Aubrey Plaza): As a representation of Death, her presence might indicate transformation rather than an end. It could symbolize a significant change or transition you are experiencing or contemplating in your life. The fact that you are shifting to your desired reality related to Marvel suggests a desire for empowerment or adventure.
2. Peeking through the window: This imagery may represent curiosity or opportunities that are approaching you. It could signify that something important is on the verge of entering your life, whether it's a new perspective, relationship, or experience.
3. Trains: Trains often symbolize a journey or a path you are on in life. The lesson you mentioned about friendships could indicate that you are evaluating the people you surround yourself with. The presence of rats and pigeons may represent feelings of anxiety or concerns about your social circles. Rats can symbolize treachery or hidden fears, while pigeons might indicate messengers or communication.
4. The abundance of rats and pigeons: This sudden increase could suggest feelings of being overwhelmed by social pressures or the realization that certain relationships may be more complicated than you initially thought.
5. The Tony Stark figure: This character, who resembles a stressed Tony Stark, could represent a version of yourself or someone you know who is struggling with responsibilities or expectations. It may reflect your own feelings of pressure related to your aspirations or the changes you wish to enact in your life.

Overall, your dream seems to encourage you to reflect on your relationships and the changes you desire in your life. It may be a good time to consider who you want to surround yourself with and how those people affect your journey. Embrace the transformation that is occurring, and don't hesitate to explore new opportunities as they present themselves.