As the title states, you can place a Sand Viper down with the "Split Vipers" passive. After the Sand Viper is placed, switch the Split Vipers sphere out for Slow Death and you will receive the increased Slow Death damage, yet still have a 3 way split on the vipers. Enjoy!
If i'm correct it's working only on training dummies, because during the combat phase you can't switch spheres. Sand vipers will be attacking enemies as long as their have target locked in, so in my opinion that's not really a big problem but would be nice to have repaired it in the future :)