UPDATE: This morning Metro confirmed our suspicions. Blink-182 will headline the venue on Thursday, August 3 with support from Elohim. Tickets are $50.50 and go on sale via Metro's website at 11am, there's a two-ticket limit and you'll have to pick them up at will call on the day of the show.
The surprise Metro aftershow seems to be a new Lollapalooza tradition, if the venue's recent tweets are to be believed. Last year, the Wrigleyville concert hall hosted two nights with LCD Soundsystem, both of which were announced long after the initial slate of post-Lolla shows. This time around, it looks like pop punks Blink-182 will be playing at least one of the three suspiciously empty dates on Metro's concert calendar during Lollapalooza.
While nothing has been announced just yet, this morning the official Lollapalooza and Metro Twitter accounts posted graphics teasing an announcement tomorrow at 10am. Blink-182's smiley face logo—which is present on its 2003 self-titled album—appears in both of the tweets, which all but confirms that the group will be playing a very intimate show at the venue on Thursday, August 3.