Plant it to grow Evil Bricks. Do not look directly at Evil Bricks.
Evil Bricks Seed price in Growtopia: sells for about 17/WL, buyers pay about 25/WL (median of 69 offers from community Discords, past 30 days). Live price chart and the latest buy and sell offers.
Recently sold at: I0YC, FN50, SIMALA, IMUPMALL, AINTSSPS