A Link Between Wormholes and Quantum Entanglement
sciencehabit writes "Theoretical physicists have forged a connection between the concept of entanglement — itself a mysterious quantum mechanical connection between two widely separated particles — and that of a wormhole — a hypothetical connection between black holes that serves as a shortcut through space (first abstract, second abstract). The insight could help physicists reconcile quantum mechanics and Einstein's general theory of relativity, perhaps the grandest goal in theoretical physics."
The observation effects the outcome. So in your example, the envelopes were sent with blank pieces of paper. You use scissors to open one letter, resulting in a nice snowflake design on the piece of paper. The other paper is now a dead cat, poisoned by the vial broken by your hubris.
I think the real riddle here is to parse your riddle.