Scouts' Hub

Forest Hub enters the battlefield tapped.
Scouts have "if this creature would die, you may pay {x}, where X is its converted mana cost. If you do, regenerate it, then put a +1/+1 counter on it."
{g}{w}, {t}: target creature beomces a Scout in addition to its other types.
Whenever a scout comes, it's sure he will return tougher than he does.