Jeff realized 2 things in that moment, the Chronivac could really do anything, and if dad was ever restored Jeff would lose the device and possibly be grounded forever.
Jeff stared at his naked dad yelling at him but not hearing words... "Yeah dad, hold on, let me see if I can fix this."
Jeff didn't know he could type this fast... Drawing inspiration from the cartoon portrayal and the long rabbit trail of thoughts he had already entertained about what he would want from a relationship with a symbiote, Jeff quickly set up a number of parameters for his dad and reality itself...
Its very rare (1-2 people/year on the planet), but occasionally a parent might become a symbiote when their last child reaches adulthood and they are alone together. Scientists haven't studied the process very well because it seems to happen randomly, rapidly, and rarely. When it does happen and the parent merges with a child, legally, the kid is now both people and retains ownership of their parents assets as long as the parent is still conscious and able to respond.
Motivations of the symbiote quickly (within a week or two) changes to unwavering support of their host and only their host. The parental role degrades to one of equals and then subservience. The symbiote offers telepathic guidance, wisdom, and to eat anyone who becomes an obstacle. Unlike in the comic, the relationship isn't parasitic for the child but for the parent. The symbiote confers a level of physical protection but over a decade or two the symbiote fades away completely. Rapid healing, extra perception, and strength are the obvious benefits but less obvious is how the symbiote can change how the host's body works.
Two hastily scrawled sentences redefining reality and a sentence saying, "Mike is now becoming a symbiote and will attach to Jeff."
Jeff presses enter and stares at his dad. "You feeling anything yet?" once 4 seconds pass...
"Yeah, Hot and naked!" Mike replies angrily.
A few more seconds pass and they stare at one another, Mike stumbles, then collapses. Mike's look of terror inspires real terror in Jeff. "Dad! What's wrong?" Jeff picked him up.
"My body, metabolism, wasn't built to be this size! I make more heat than I can get rid of." With that he began to melt.
"Dad!" True horror gripped Jeff a he thought his father was dying, but the puddle in his hand began to blacken and cling to him, shooting tendrils that stung as they pumped themselves into his flesh, a new horror took him as his dads body clung to him and pumped its way inside of him with vigor. Within a minute it was over... Jeff was around 25-30 lbs heavier and all that was left was a pile of clothes that represented his father and a strange moving sensation inside him... What had he done?