I am newly invented words that replace old ones. When spoken, I confuse the old and entertain the young. What am I?

Forwards, I'm contagious Bumpy blemishes of hags and toads Backwards, I'm advantageous Preventing spills while drinking on the road

Drop me in the right substance and I'll make it explode. I also taste alright on my own.

Pull on an end and you have a bang. Add some cheese and you have a canape. Light me on fire and you have a riot of colour.

We rise from the pond on a warm spring day, Far too small for a knight to slay, Flitter and shimmer like fairies at play, While keeping the backyard vampires away!