quickly placing my concept of the 10-year-old segment onto the table before 6.6
Based on my "Red Wine" fic, I headcanon that little Zandik had big, uncanny eyes that creeped everyone out, but the shape of them mellowed when he grew older.
I actually think Zandik was probably more "chill" (as in just not caring enough to get pissed) when he was a kid, but the child segment is more hostile towards adults because he's been alive for hundreds of years and the other segments dismiss him and treat him like shit, so he's grown some extra resentment and learned to defend himself.
He enjoys people-watching and likes to play with Columbina. Pantalone is also cool in his book. They have a unique bond despite Theta normally hating adults and Pantalone normally hating kids.
Any other adult will be met with either venom or a dead look. Please refrain from putting your hand near his face or head. He will bite. And if you're Webby, you will also receive a complementary punch in the nuts or a kick to the shin. Only Webby, though. They hate each other the most. :)