This spell can't be countered. Sliver spells can't be countered.
Legalities
Legal
Duel
Predh
Legacy
Vintage
Commander
Premodern
Oathbreaker
Not Legal
Brawl
Penny
Future
Modern
Pauper
Alchemy
Pioneer
Explorer
Historic
Standard
Timeless
Gladiator
Oldschool
Standardbrawl
Paupercommander
Rulings
2013-07-01
If the creature type of a Sliver changes so it’s no longer a Sliver, it will no longer be affected by its own ability. Its ability will continue to affect other Sliver creatures.