Invaders, which is composed of six stylized butterfly sculptures, was transferred to Building 44 in 2003, when the works original site, Building 45, was demolished. The artist wanted to inject a playful and whimsical spirit into the site at Building 45, which was gritty and industrial. The butterflies are constructed of wrought iron and steel, materials common to the industrial arena, and embellished with colored and mirrored Plexiglas, colored marbles, and fluorescent paint, all of which add a lighthearted note.