Originally Posted by Fat SpecsX
Because Stealth Rock strips away 50% of its health upon switching in. You should add a spinner to the teammates section. (Rapidash is weak to Stealth Rock too, by the way)
Honestly SR isn't as big a deal as everyone makes it out to be you just have to be prepared for it. It's really all about your play-style. If you can't find a way around SR then tough nuts for you (not you personally SpecsX).
And I guess i should post an RMT for my NU team to show how I use Articuno.