You've learned Charge Flame! To use this ability, hold X to charge, then release X to detonate and damage everything in proximity!
Charge Flame is the third skill Ori learns. It is an offensive attack that consumes one or less Energy Cells and damages any enemy within a certain radius of Ori. It can be used to remove Breakable Barriers which seal off areas that could hide secrets or important pickups. The damage radius, damage intensity, and energy cell cost of Charge Flame can all be improved by upgrading Ori's Ability Tree on the Offensive Branch.