Things and people, or in this case the band, can vanish leaving artifacts behind (something made or given shape by man). You're thinking I said "... it's as if HTDA in its whole entirety and material vanished". I also paraphrased by explaining "setting an atmosphere for the group and the LP; and follow up to the EP"
My apologies if you didn't understand my post, I do rant and misuse semicolons often.