Lulu's passive, Pix, provides extra attacks for herself or an ally, depending on who Pix is currently following.
What does this damage scale from? Does it scale with AD, AP, etc.? Is Pix's damage Magical or Physical? Does Pix attack when the ally uses spells, or just for autoattacks?
Here are the answers to this question(s) one-by-one:
What does [Pix's] damage scale from?
Pix's damage scales with Lulu's level. The formula for Pix's damage is:
Pix fires a barrage of 3 bolts, dealing 3 + (2 × level) magic damage each
Does it scale with AD, AP, etc.?
As you can see from the formula above. it does not scale with Attack damage (AD), Ability Powers (AP) or any other champion stat (Mana, Health, etc.) and is based solely on Lulu's level.
Is Pix's damage Magical or Physical?
Pix deals magic damage exclusively. Therefore his damage is dependent on the users Magic Penetration and the targets Magic Resist stats. There is some speculation about whose Magic Penetration Pix uses when making his attacks from an ally (not Lulu) as noted in this link.
Does Pix attack when the ally uses spells, or just for autoattacks?
Pix's attack is triggered by autoattacks only. Casting spells that refresh the attack animation (Nasus's Siphoning Strike, Blitz's Power Fist, etc) may provide additional attacks from Pix but to maximize the damage you probably want to target a champion with a higher attack speed.
For more information about Lulu and Pix check out her entry on the LoL Wikia.
When you cast "Help, Pix!" and the recipient targets a tower does it add damage or does Pix only attack other units? The description of the skill reads: "If cast on an ally, commands Pix to jump to an ally and shield them. He then follows and aids their attacks." So, does Lulu's passive (and the associated "Help, Pix!") add damage when attacking structures?
As Lulu, you can redirect your passive using Help, Pix! and give it to an ally. Upon doing so, you can use her other ability, Glitterlance, and aim it from yourself and the ally you used Help, Pix! on. What happens if the ally is teleported or moved across the map shortly after your ability? Can you sit in your base and use the abilities in tandem to help, say a Shen, track down a target and slow them with Glitterlance to get an across-the-map Assist (or KS)?
Lulu can cast Help, Pix! on allies and enemies. If she casts it on an ally, Pix's magic missile barrage attack triggers on the ally's auto attacks. If an enemy is killed as a result of this damage (rather than the triggering auto attack) is Lulu granted the kill or is her ally granted the kill?
When a Lulu puts her shield (E) on a teammate, every time they auto-attack Pix also fires a bolt. Does this bolt "count" for Lulu or that character? For example, let's say your AD carry is trying to get red buff. You, as Lulu, put your shield on them. Now every time the AD carry auto-attacks, there is a Pix bolt added to it. If it just so happens that the damage from Pix's bolt is what kills the Elder Lizard, will Lulu end up with the buff? Or will the AD carry still get it? The same question could be asked for champion kills. If it counts for Lulu, this seems like a big hazard
As Caitlyn, I used my ultimate on a very low health Lulu that had her skills (including her ultimate) on cooldown. She started to run away, my ultimate went off, and my ultimate did not hurt her even ...
Will the stealth effects of Akali's Twilight Shroud cancel the vision granting effects of Lulu's Help, Pix! spell?
"Pix, Faerie Companion" also known as Lulu's passive is a small fairy (or faerie?) that fires along side with you, and a few other things. Is there anyway for me to make it move to a certain position without moving/rotating Lulu or using an ability (ie protect/shield)?
I was wondering if Pix's 3 hits count for things like Ionic Spark or proc the effects of Wit's End. If nothing else, does Spell Vamp proc off of their dmg?
In RockSmith 2014, there's a game called Scale Warriors. At the end of each level, you go up against a big red dude. Sometimes when I try to hit Big Red, he raises a shield to block the attack. Unlike the shield in Ducks Redux, this one does not seem to be affected by taking a series of hits. And because no other scale notes are lit up, it doesn't seem possible to retreat, either. Are my Scale Warriors inevitably going to take damage once Big Red raises his shield? Or is there something I can do to avoid it?