Can I sacrifice a creature, then regenerate it?
No. Regenerating prevents a creature from being destroyed and sacrificing doesn't destroy things
Nope. Nothing can save a creature from sacrifice.
It doesn't even use the stack! (Though the ability/spell causing sacrifice most likely does).
Ok thanks
{Reassembling Skeleton} sure u pay one black and a colorless but it comes back to the field
Or {Tenacious Dead}
Pff all about {sigarda, host of herons} just don't sac your own things