Even though he is a scary monster (i.e. Dracula), no matter what he is still a corny, cringe-y dad. The contrast is meant to be lightly humorous. Most of the time the joke is in the wordless expression of the son as he reacts to his dad’s shenanigans.
EILI5
I get the dad being an alien, “the truth is out there”, and him being wholesome, but where does dad also being Dracula factor into the joke?
Even though he is a scary monster (i.e. Dracula), no matter what he is still a corny, cringe-y dad. The contrast is meant to be lightly humorous. Most of the time the joke is in the wordless expression of the son as he reacts to his dad’s shenanigans.