If cards are removed from your graveyard after that point, such as by exiling Jack-o'-Lantern from your graveyard to pay for its mana ability, this won't affect whether you can legally cast Graveyard Shift, even if that reduces the number of mana values in your graveyard to below five
Instead, tap it, remove all damage from it, and remove it from combat if it's attacking or blocking." Regenerate Does Work Against Lethal Damage When a permanent Regenerates, all damage marked on it is removed, which is why Regenerate works against lethal damage
Chart shows the price of Sprigatito #76 at the end of each month going back as long as we have tracked the item.
You can also use it in reverse, putting a shadow counter on an opposing creature and making it unable to block anything without shadow
If you want a picture of power creep, this card is a great example