What do you think would have happened if Carl and Frank had developed the spark after Verdona left Earth? What kind of changes would that have caused in their family relationship? How would Sandra or Natalie have reacted? How would Carl and Frank have felt about it? (I'm thinking of writing a fanfic that explores this psychological aspect and I wanted some different perspectives to inspire me. I'm a big fan of "It Was Automatic" and "Glitch's Spark," they were my biggest inspirations. Sorry if this is a bother.)
Totally not a bother! Always love talking about fics/Ben 10, and I'm really glad you liked those two fics of mine!
I outlined a fic years ago where Carl and Frank got the spark as kids, but I never ended up writing it. Cannot find my notes for the life of me, but I think it took place before Verdona left because it was a lot of Carl and Frank not understanding what was happening to them, versus they would probably understand what was going on if it happened after Verdona left, which makes your fic idea really interesting to me!
Sorry for the long ass a response, but I do want to answer all your questions/I think this is very interesting
What do you think would have happened if Carl and Frank had developed the spark after Verdona left Earth?
If I remember correctly, Verdona left when Carl and Frank hit adulthood, so they were probably off at college when she left. How they find out about Verdona's powers can definitely very, but I always imagined they found out when they left, which I think would really change the meaning of the spark when they got it.
I think the psychological aspect could be a lot of confronting the fact that they're not human, which is, you know, bad and scary, but also feeling this connection to their mother after she left, maybe with some element of having to repair their relationship with Max since he is now their only source of information on alien stuff (more on that in the next question).
The main reference point we have for how humans react to sparking is Gwen, but Carl and Frank wouldn't necessarily have the resources she had. They wouldn't have a magic book or dangerous adventures to teach them to hone their powers. They'd probably only be able to manipulate hard light on a basic level, and they would be more focused on the implications of being an alien, or as you said it, the psychological aspect.
What kind of changes would that have caused in their family relationship?
If I were writing it, I would also probably have some focus on this relationship with Max just because I enjoy exploring my personal experiences with loss and grief through fanfic, and I find it interesting for characters to have these major, massively life-shaking moments and reassess what is actually important to them
With Max, there would also be the confrontation about his life as a Plumber. In canon, Frank and Carl have a rocky relationship with Max because of how often he was gone, so I think this bomb being dropped that he was off fighting aliens and their mom was an alien and he never told them would make it difficult for them to properly deal with losing Verdona and relying on him after they spark.
I also think it would be interesting if Frank and Carl sparked at different times. Again, if I were writing this, I would be compelled to write it this way because of my personal experiences with grief, loss, and major life changes while away from a sibling.
Through my reflections on my own experiences, my philosophy on what it's like to have a sibling is that in childhood, you are sharing your life in every way. You have the same memories, and you experience these big, scary moments together, especially when those moments are centered around the family.
But when you reach adulthood, that changes. You experience this huge thing, and your sibling isn't with you, and you eventually have these moments where you realize your sibling just doesn't understand, which is very jarring because it's never been that way.
I imagine Frank and Carl weren't at home when Verdona left, so they learned of her disappearance independently, and I imagine things were different between them, and they came back home to deal with it and realize they had to process it all independently.
And if one sparks but not the other, you have these two wildly different experiences again, and they may not necessarily understand each other, which I think would be very interesting to explore (more on that in the question about how they feel about it).
How would Sandra or Natalie have reacted?
If I remember correctly, Sandra was portrayed as a little wacky and generally open minded versus Natalie was stricter and more conservative. Sandra does eventually come around to fully embracing alien stuff, and I think Natalie found acceptance but didn't want it to be an active part of her life, more out of love for Frank and Gwen than any of her beliefs about aliens.
It would totally depend on whether Carl and Frank were in relationships or not when they sparked. If they were already together, I could totally see it as a figuring-out-together type of thing. If not, I imagine Carl and Frank would be worried about their future love lives, when they'd have to tell someone they're an alien, etc etc.
I imagine they'd react the way anyone would and kind of not believe them at first, then be a little freaked out at first. I think Natalie would need some space to process it, and Sandra would lean into it a little more and want to learn more. But again, I think it would totally depend on where any of them were at in their relationship.
How would Carl and Frank have felt about it?
Kind of like I got at before, I think some major themes of processing the feelings would be this fear of being something inhuman and feeling connected to their mom because of it. Pretty mixed feelings.
Carl and Frank don't have a ton of canon personality, so you could definitely take some liberties to develop them a little more. The main thing we see from them is that Carl is a little more liberal and Frank is a little more reserved.
I could see Carl wanting to talk about it/learn more vs Frank wanting to hide it.
If they sparked at different times, I could see Frank sparking first, hiding it, then Carl sparking and wanting to talk about it, but being upset when he learns Frank hid it. I could also see Carl sparking first and wanting to explore it, but Frank being worried about Carl getting caught, and/or having mixed feelings about Carl getting this connection to their mom.
Given Max was away a lot when Carl and Frank were kids, I do think Carl and Frank were very close with Verdona, and thus their feelings about her leaving would impact their feelings about their sparks.
Depending on your comfort level, I'd maybe do some reading on biracial and/or second-generation immigrant experiences. I think that a lot of the feelings people have about assimilation and retaining connections to their homelands/parents' cultures could provide some insights into what Carl and Frank are feeling. That's kind of where my "feeling connected to Verdona" mindset comes from.
Like I mentioned before, my personal experiences often influence my writing, and my experiences with loss totally affect how I look at this, but also my experiences as a biracial and trans person. I would definitely recommend thinking about if there are any parts of Carl and Frank's story here that you relate to and lean into those elements.
I would love to read your fic if/when you post it! Also happy to talk more if you need to idea bounce