With the latter effect, you can discard a level 5 "U.A." and revive it with "Feast of the Wild LV5"
"Commander ninjutsu [cost]" means "[Cost], Reveal this card from your hand or from the command zone, Return an unblocked attacking creature you control to its owner's hand: Put this card onto the battlefield tapped and attacking." Commander ninjutsu is a variant of ninjutsu that can be activated from the command zone as well as from your hand
Up until now we only had one "free all the time" Counterspell in Decree of Silence that was a hard counter with its cycling trigger, and other counters that were sometimes free needed conditions, like Force of Will's pitch ability
The card is a staple of Modern Titanshift archetype and now it can be played in Standard as well
This is where modal spells can squeeze in that little bit more functionality
With a healthy package of auras, equipment, and pump spells, you can easily protect Krenko from dying in combat while generating more and more Goblin creatures