SILENT BUT DEADLY. A low noise compound cake from Celtic Fireworks. SILENT BUT DEADLY. A low noise compound cake from Celtic Fireworks. A wonderful quiet, long duration cake with a real range of interesting and colourful effects. Silver chrys tails with mines, spit dahlias, fish, colour mines. Spit horsetails, colour pearls and finishing with silver. If you have any questions about Silent But Deadly then please contact Edinburgh Fireworks Store.