Any boss that can dodge something without tracking could dodge it with tracking. Let's go down the list Could This Boss Dodge Gjallarhorn? Sepiks Prime-Yes, he can teleport, making tracking useless. Phogoth-No. Even without tracking, Phogoth doesn't move fast enough to dodge a rocket. Sekrion-No. Although Sekrion has a decent moving speed relative to its size, its still very large and hard to NOT hit. Plus, if Sekrion is aggro on you, it will move towards you until it reaches its movement boundary. Valus Ta'aurc-No. Valus has a small weak spot, but he still moves very slowly, when he does move. Omnigul-Yes. Omnigul, being a wizard, uses sudden bursts of agility capable of avoiding almost all rockets with tracking. Taniks-Yes, but not likely. Taniks teleports, but not randomly. He will stay in certain areas of the arena for extended periods depending on his health/time he has been in the arena. It's an easy hit when he first spawns, but if you launch right before he teleports, you will not hit him. Askor-Yes. Highly likely but not garaunteed. Askor is a Captain, meaning he will teleport alot. Given his special programming as a boss, he will teleport more than a standard Captain would. If he's aggro on you or a teammate, he probably won't teleport at risk of losing his aim. You can hit him then. I don't know about the Dust Palace boss, but I know they're Psions, meaning they probably can't teleport, but they're small, like to hide, and probably not worth the risk.