Line a large baking sheet with parchment paper or a silicone baking mat. Make sure the surface is flat so the coated pretzels can set without sticking or losing their shape.
Place the white chocolate and vegetable shortening in a microwave-safe bowl. Microwave in 15–30-second intervals, stirring thoroughly after each interval, until the mixture is smooth. Stop heating while a few small pieces remain and stir until they melt from the residual heat.
Add 10–15 pretzels at a time to the melted chocolate. Toss gently with a spoon or spatula until coated. Work in small batches to keep the pretzels from clumping together and to help the chocolate stay smooth.
Lift each pretzel out using a fork or kitchen tongs. Gently tap the fork against the side of the bowl to let excess chocolate drip off. This creates a thinner coating and helps the pretzels retain their crunchy texture.
Place the coated pretzels in a single layer on the prepared baking sheet. Leave a little space between them to prevent them from sticking together as the chocolate sets.
Immediately decorate the pretzels with Halloween sprinkles while the chocolate is still wet. Use orange, purple, green, and black sprinkles for a classic Halloween look. You can also drizzle a contrasting color of melted candy coating over the top.
Allow the pretzels to set at room temperature until the chocolate hardens, or refrigerate them briefly to speed up the process. Once firm, gently lift them from the parchment and transfer them to an airtight container or serving platter.
