Feel that in the morning!
The skill is located towards the end of Auron's section of the Standard Sphere Grid, though a Lv. 4 Key Sphere is required to reach it. On the Expert Sphere Grid it is located near the beginning of Wakka's Sphere Grid, and a Lv. 3 Key Sphere is required to reach it.
Although the skill is found on Auron's section of the Sphere Grid, only Wakka has a quote when using it, like the other Status Attacks, suggesting the attack is meant for him. Zombie Attack being in Auron's grid might allude to his unsent nature.