What are these, Boobs?

In the first Umineko stream, a character named Battler has a character trait where he is obsessed with boobs and constantly goes in to grope them. At one point in the story, Battler sees his cousin, Jessica, for the first time in six years. He comments that her breasts have grown bigger since the last time he saw her with the line "What are these, boobs?" Joe picked up on this and it became a stream joke after the story uses the trope a couple more times, cementing it in stream history.