Talk:Serration/@comment-28891726-20160701011801/@comment-25254386-20160701022852

Actually...that's pretty much exactly it. Any Grineer Scorpion can drop it, any Infested Electric Crawler can drop it, any Infested Nauseous Crawler can drop it, any Tier II Defense on any planet can reward it, any Tier I/II/III Survival on any planet can reward it, any Spy Mission on any planet can reward it.

But you should note that Scorpions normally spawn on Grineer missions which are most common on Mercury, Saturn, Uranus, Phobos, etc. while Crawlers spawn on Infested missions which are most common on Eris.

So try a Tier II Defense on Mercury or Saturn that way it has a chance to drop from both the mission rewards or a Scorpion.