Amazing Skeleton snowflake by She Walks Softly Author and a great demonstration of rotational symmetry.
A wide variety of creepy snowflake templates can be downloaded from PaperPumpkins
A rotational spider template can be downloaded from New Halloween Games here.
These snowflakes are great and look amazing when done but they require a steady hand. Instead you could ask pupils to create their own spooky snowflake with a given order of symmetry.
Join this activity with the hama bead activity described in Hama Bead & Symmetry blog here for another rotational symmetry activity, you may want to buy extra orange and black beads for Halloween!