: Put a +1/+1 counter on this creature.
to cast Walking Ballista.Walking Ballista turns a variable mana investment into a creature that can deal damage without attacking. Its two X symbols mean you pay twice the chosen X to cast it, and it enters with that many +1/+1 counters before other effects apply. Removing a counter deals one damage to any target, giving the card uses against creatures, planeswalkers, battles, or players.
Counter support makes the investment more efficient. Branching Evolution or Doubling Season can increase the counters it receives, and its four-mana activated ability provides a way to add counters during a longer game. Ballista can also spend counters in response to removal, converting some of its remaining size into damage before the creature leaves.
Heliod, Sun-Crowned enables a specific loop. Start with Ballista holding at least two +1/+1 counters, then use Heliod to give it lifelink. Remove a counter to deal one damage. The resulting life gain triggers Heliod, which can replace the removed counter on Ballista. Repeating the sequence can produce enough damage to finish opponents while the abilities continue to resolve successfully.
Starting with only one counter normally causes Ballista to die as a 0/0 after removing it, before the loop can restore the counter. Prevention, removal, or effects that stop life gain can also disrupt the sequence. Outside a combo, Ballista remains a flexible outlet for excess mana, especially in decks that naturally generate large amounts or support +1/+1 counters without needing the full Heliod setup.
