Dual Nature

Whenever a nontoken creature enters, its controller creates a token that's a copy of that creature.
Whenever a nontoken creature leaves the battlefield, exile all tokens with the same name as that creature.
When this enchantment leaves the battlefield, exile all tokens created with this enchantment.

Yisan, the Wanderer Bard

{2}{G}, {T}, Put a verse counter on Yisan: Search your library for a creature card with mana value equal to the number of verse counters on Yisan, put it onto the battlefield, then shuffle.

Satyr Piper

{3}{G}: Target creature must be blocked this turn if able.

Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Permeating Mass

Whenever this creature deals combat damage to a creature, that creature becomes a copy of this creature.