It's like, if the spell does damage directly to it.. the totem will die (only 5 health).
Mana burn makes mana -> damage, no mana, no damage, totam is alive.
All sort of magic spell that does not do direct damage on impact wont kill it either.
Like a dot, the totem won't die because the dot has not ticked, and it can't since a totem is immune to dots.
Also it will rebuff the grounding effect within 3-5 seconds.