Marc “Coop’’ Cooper is the man behind the drippy lid. That’s what he calls the packaging that holds his Coop’s Hot Fudge (about $8 for 10 ounces). The jar looks like it’s been dipped in fudge (it’s actually nontoxic wax). Cooper originally developed the jar and sauce for Herrell’s. When they parted ways, he took the dripping packaging with him and tweaked the product inside, adjusting the formula with Cabot butter, Callebaut chocolate, and molasses. The result is a deep, complex sauce that, says Cooper, many customers spoon straight from the whimsical jar. Available at A. Russo & Sons, 560 Pleasant St., Watertown, 617-923-1500; Berman’s Wine and Spirits, 55 Massachusetts Ave., Lexington, 781-862-0515; Roche Bros. Supermarkets; Shaw’s supermarkets.