Hollowheart

On the 6th anniversary of "Worlds", Porter Robinson tweeted:

"on worlds 10th anniversary i'll share a song called "hollowheart" that was supposed to be on the album but i submitted it too late"

Porter provides additional background info in a Twitch livestream (approx 1:06:03 to 1:08:47) on 2024-05-15. (YouTube mirrors: 1, 2)

{ should link these (1, 2) tweets where porter releases hollowheart). oh and this tweet about its place in the tracklisting }

The track incorporates some elements from previously leaked works from Porter such as the vocal sounds from "OSTTT" or the piano melody from "A Sound From Lonely People". There are also snippets of "Hollowheart" present in the Worlds live show (demonstration)

Apparently, the vocal chops from Porter Robinson's and Madeon's "Shelter" originate from the Amy Millan vocals for Hollowheart, with some people being able to partially recreate the "Shelter" vocal chops using the "Hollowheart" vocals (examples: 1, 2). This is further backed by Porter Robinson previously revealing the vocal chops for "Shelter" come from Amy Millan's vocals for a song that got recorded at the time of "Worlds" and might be released at some point.

Before release, a number of IDs were rumored to be "Hollowheart", such as the Bellwether ID and this CIVIC Underground 2014 ID

See also: Hollowheart on the Porter Robinson Wiki