Preheat oven to 350°F.
Line cupcake pan with papers.
Mix flour, sugar, cocoa, soda, salt.
Add water, oil, vinegar, vanilla.
Beat until smooth and combined.
Fill liners two-thirds full.
Bake for 18-20 minutes.
Let cupcakes cool completely.
Cut small holes in centers.
Mix jam with red coloring.
Fill holes with red mixture.
Frost cupcakes with buttercream.
Shape fondant into fangs.
Insert fangs into frosting.