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Something to keep in mind about Mega Pinsir that I've not seen mentioned is that Feint is a non-contact move, so Ferrothorn and Tankchomp can't wear it down as easily. And that it's basically espeed pinsir with a higher bp espeed. It's not as much of a terror people think judging from myself...
I'm going to keep this in perspective of an offense player. Chansey is something that you need to build for no matter what. If you don't have something to bait it in that has knock off and a competent physical answer it will face roll your team.
"competent physical answer" would mean a lot of...
This isn't like aegislash where it can run several different sets and take down a poke on the guessing game alone while having great offense and defense presence. It's a cannon. It can get great hits out on a good portion of OU, but it can't sweep as easily as, say mega charizard x or mega...
Good defensive typing and stats are one thing but what makes Aegislash so great is its ability to run many different sets and the mind games it causes. The most common ones are quiet mixed shadow ball nuke and adamant swords dance, but I've seen success with automize weakness policy, toxic stall...