But apparently the die inside a magic 8-ball is a 20 sided die.
I would've thought maybe a D10 at most, i have vague memories of playing with them while young, but really only remember maybe 5 or so answers, despite probably goofing around dozens of times with the thing.
I saw a short on YouTube about a D&D group's oracle being a magic 8 ball and none of the party members (in character) knowing what that even was. While browsing some of the comments, it was mentioned that the die inside one of those things was a D20, and I was like, "that can't be right...."
I had to look it up afterwards and here's what i found:

The Magic 8 Ball contains a 20-sided die with 10 positive answers, 5 negative answers, and 5 vague responses

Now granted, that's for a standard 8-ball, so i'm sure there are some variations out there that have different types of dice and messages....

Late night YouTube video watching strikes again :P