Almost everyone knows that a special card can be negated. A few people know you can negate a special when opponent plays it. Some people believe you can negate a negative special card. Two negatives do not equal a positive, I'm sorry. This as Overpower's playbook says, "You cannot react to a reaction". They created this rule to eliminate endless loops of negative actions. When they made you unable to reacts on a reaction they also made you unable to react on avoids. Since avoids are reactions, so avoids cannot be negated (unless it is played as an attack). Thank you, and happy playing.
Offical Websites Negative Rule - http://www.overpower.com/rules/negate.html