Standard Skill
Mauxir creates a target Avatar from the target enemy. Damaging the Avatar damages the host enemy. [The Avatar is not an auxiliary unit.]
The host takes 110% of the damage dealt to the Avatar.
Shots hitting the Avatar only give half of their U-Energy.
With its second Neuronic, defeating the enemy will reset the cooldown of the skill.
Since the host takes extra damage if the Avatar is targeted, you should always target the Avatar.
Support Skill
Just like her standard skill, Mauxir creates an Avatar from the target host enemy, and damaging the Avatar damages the host.
The Avatar from her support skill:
Lasts 8s instead of the 16s from her standard skill
Has only half the current HP of the host, rather than equal to its current HP
Only transfers 60% of the damage, not 110%
Can't be hit by shots (so skill damage only)
If you have some AoE damage, then you can use Meow's support skill to create an extra target for it to hit.
With its first Neuronic, it can be used to create targets from multiple enemies, allowing you to deal much more AoE damage.
With its second Neuronic, Meow automatically uses her support skill whenever any operative inflicts a control effect on the target.
This does not start a cooldown on her support skill, and you can use them after one another for high uptime.
When used with operatives that frequently inflict control effects (e.g. Lyfe - Wild Hunt) this can allow Meow very high uptime on her support skill.
Since it can't be hit by shots, and it transfers less than 100% of its damage to the host, you shouldn't aim at Meow's Avatar.
Instead, use AoE effects to hit both the Avatar and the host, allowing you to deal more damage.
Ultimate Skill
If the targets HP is lower than 150% of Meow's current HP, the enemy takes damage equal to its current HP, effectively instakilling it.
If the targets HP is higher than Meow's, then Meow's shots gain Frost aptitude - extra Frost damage per shot.
The extra damage can trigger up to every 0.5s, per target.
The extra damage is based on Meow's HP rather than her ATK. As such, +15% per shot is a lot of extra damage.
With her second Neuronic, other operatives gain the Frost aptitude effect.
With its first Neuronic buff, killing a target with her Ult refunds Meow with 90% of the U-Energy used and resets the cooldown of her ult.