Heavy Bolt Cannon is a legendary major card out of the New mechanic pool. Arc Bolt becomes one slow cannon shot: 200% damage, 3 pierce, 2 u knockback, but the cast is 60% longer.

You can take it once · it only turns up when your Main ability can actually use it · it can be offered for 0 of the 34 abilities.

Only one card can reshape that ability this way — this one, or Storm Lattice and Orbital Bolt. Take one and the rest are gone for the run.