Early last week, street artist Christiaan Nagel left a capped surprise above the doorway of 190 Bowery at Spring Street. Based in London and operating around the world, Nagel has gained recognition for his brightly colored spores that seem to burgeon into existence from one moment to the next, usually atop roofs like this one in the Bowery. According to Street Art London, the mushroom sculptures are made out of polyurthane syrfboard foam, fiber glass and stainless steel.

Why mushrooms you wonder? In an interview with Tom Du Croz, the South African native reveals that the idea came about accidentally after an experiment with those materials led to something resembling a mushroom cap.

While in the city, he also left his mark in Queens at 5 Pointz, as evidenced by his own Instagram account. To see more of Nagel’s worldwide mushrooms click here.