I block Boggart Ram-Gang wither creature with Skeletal Kathari can i regenerate??

[mondek]

If I use Skeletal Kathari to block Boggart Ram-Gang (creature with wither) can I regenerate the skeletal kathari?

[Arix]

You can try, but it won't do a lot of good.

Damage is dealt to the Kathari in the form of -1/-1 counters. Three counters are put on it, making it a 0/-1 creature. The next time state-based actions are checked, they see a creature with 0 or less toughness and ship it off to the graveyard. This doesn't count as destruction, so regeneration doesn't stop it.