From what I can tell pieced together by Tumblr posts, DashCon is/was supposed to be a fan convention for Tumblr. And all I've managed to piece together so far is that there was a ballpit at some point, Welcome to Night Vale came and was not paid and so did not do a panel, apparently there's a ballpit of some sort, and people tried to sing Les Mis.

And also something about the con scamming people at the con for $17,000 or else the hotel would kick them out.

But I'm having trouble tracking down those posts again because I saw them on Tumblr and what is trying to track down anything</a> on Tumblr. This is all I've managed to find so far also warning autoplay music.