Why is ice beam super effective against my rhyperior?

[KingOfClubs]

It's a rock/ground type, yet a blissey with ice beam got 4x damage on it... I thought Ground was x2 but rock was .5x so they cancelled each other out...

 

[Usagi-Chan~]

pretty sure ice is effective against on of those types

 

[brotlov]

Ice is x2 on a Rhyperior, it's super effective against ground, it's normal against rock, Ice Beam is also a Sp. Atk move, so check your Rhyperiors' stats, it might have shocking Sp. Def

 

[robbman14]

Ice does 200% to Rhyperior but it's Sp. Def is terrible. How would you know it was 400%?