Discard as many [M] Energy attached to this Pokemon as you like
Declare Blockers Step After you've declared your attackers, your opponent will have the option to block your attackers with any uptapped creatures they have in play
Second, Korvold can be your Jund commander, and a fairly powerful one at that
Like most Pokmon cards, the value of Ditto depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Detective Pikachu)
Even better, it has the Hideaway ability, letting you dig five cards deep into your deck and tuck away a spell, ready to cast it for free later when you meet a particular criteria: in this case, having three creatures with different powers after you tap Collector's Cage