Title text:
'This HAZMAT container contains radioactive material with activity of one becquerel.' 'So, like, a single banana slice?'
Transcript:
[Cueball holds a stick while talking with Megan and White Hat.]
Cueball: This stick is one meter long.
Megan: Cool.
White Hat: That's a nice stick.[Cueball holds a smallish rock.]
Cueball: This rock weighs one pound.
Megan: I'd believe it.
White Hat: Looks like a normal rock.[Cueball holds a small battery.]
Cueball: This battery is one volt.
Megan: Seems fine.
White Hat: Might need a recharge.[Cueball holds a capacitor while Megan and White Hat panic.]
Cueball: This capacitor is one farad.
Megan: Aaaaa! Be careful!!
White Hat: Put it down!!
Source: https://xkcd.com/3106/
Their names are Cueball, Megan, and White Hat?
It is my understanding that XKCD's "characters" are somewhere between an actual character and an archetype. It isn't clear...and kind of doesn't matter, if Black Hat is the same guy in every comic or if he's a different devious schemer in each. Randall hasn't bothered to name any of them so the community has given them unofficial nicknames.
Megan is actually named in multiple comics though, ~~so is Danish (Black Hat's girlfrenemy)~~ (actually that was picked semi-arbitrarily by the community). Cueballs also have different names occasionally but they're all drawn the same.
And actually I do believe that certain non-named characters are the same comic-to-comic. Black hat and Beret guy almost certainly are.
Yeah Black Hat called her "My dearest darling danish" after she called him "my cutie pie." Closest thing she's had to a name.
I remember reading about their names in explainxkcd. I think the only one never named in the comics is Cueball.
For a while, there was a blog, but I don't think it named any character.