I don't see a reason for this creature to be poisonous. If it's something related to the card name, please explain, but in any case, not fitting.
And while I'm not sure whether its health is too high, I do agree with skyironsword that a cost increase isn't necessary.
If receive 15 damage of once, produces 1 spark or 15?
I'd assume that it produces just 1 spark. It doesn't say anything about 'every 3 damage, produce Spark | every 5 damage, produce Ball Lightning'