All of the above aside, I'd also highly recommend grabbing the Disney Lorcana app for your phone
Yes, Walking Ballista has its own self-replacement effect that modifies how it enters the battlefield: Instead of just entering the battlefield, it enters with X +1/+1 counters
Source: Final Fantasy /Facebook Main Genre Fantasy Release Date August 5, 1993 Created by Richard Garfield Character(s) Jace Beleren, Chandra Nalaar, Liliana Vess, Garruk Wildspeaker, Nissa Revane, Ajani Goldmane, Nicol Bolas, Teferi, Gideon Jura, Sorin Markov, Ral Zarek Video Game(s) Magic: The Gathering, Magic the Gathering Commander, Magic: The Gathering - Battlegrounds, Magic the Gathering: Duels of the Planeswalkers 2012, Magic: The Gathering - Duels of the Planeswalkers, Magic: The Gathering Duels of the Planeswalkers 2012, Magic: The Gathering Duels of the Planeswalkers 2013, Magic: The Gathering Duels of the Planeswalkers 2014, Magic: The Gathering Arena
If not a reskin, I would bet this is the artwork for a board wipe in the set