Ikaru

For reference Normal Kenga has 95 base attack, where Greninja has 103 Special Attack. Mega Kenga, is not only much bulkier than Greninja it also has more raw power. So it is a combo of it's increased stats, and Parental Bond, not Parental Bond itself. (and it is only a 30 base attack increase, my bad. It also got 10 in speed, and 20 in both defenses, that is what makes Mega Kenga broken more so than the ability in my eyes.

It's the fact that it gets doubled effects and hits past sashes and subs that makes it broken, not so much the raw power

my reaction: http://i3.kym-cdn.com/photos/images/newsfeed/000/774/188/32a.gif