Bake cake layers as per box instructions (3 pans). Cool completely and level.

Make banana pudding by mixing all ingredients until smooth and fluffy.

Beat frosting ingredients until creamy and thick.

Assemble: Pipe frosting barrier on each layer, fill with banana pudding, stack, and repeat.

Frost the outside, sprinkle with coconut, drizzle caramel on edges, and decorate with frosting and Nilla wafers.

Chill for at least 1 hour before slicing and serving.