What it does
Lunge hits the target and, if the move connects, drops their Attack one stage every single time. That guaranteed trigger is everything. Compare it to Struggle Bug: that one has a chance to lower Special Attack on both foes, while Lunge locks in a physical Attack drop on the target you choose.
In doubles, Attack drops scale directly into team survivability. Shaving one stage off the opponent's main physical attacker can be the difference between your tank surviving a key hit or getting knocked out. The effect stacks with Intimidate, so a partner who carries that ability plus a turn of Lunge can stack the target down to -2 Attack — cutting their physical output roughly in half.
Who runs it
Heracross runs Lunge at a 44% usage rate, making it the primary carrier. Heracross is a dedicated physical attacker, so Bug STAB is genuinely useful here — but the Attack-drop utility is what earns the moveslot. It damages the target and debuffs them in the same action.
Araquanid uses Lunge at about 15%. Araquanid's claim to fame is Water Bubble, which doubles its Water-type power and halves incoming Fire damage — but Lunge is chosen for the Attack-drop effect more than the Bug STAB damage. Araquanid leans toward a bulkier, support-oriented role, and Lunge lets it contribute utility pressure without giving up an attacking slot.
How to use it
Lunge is single-target. Against two physical threats on the field, you have to pick one — usually whichever is faster or more immediately dangerous. If the partner can redirect, Follow Me or similar can buy space to use Lunge safely.
Timing matters. Early in the game, before any Intimidate has landed, Lunge can preemptively suppress the foe's primary physical attacker. Later in the game, after Intimidate has already fired, Lunge stacks on top for -2 total, which is a very different threat level to be working with.
Watch for Protect. If the foe reads your intent and Protects, you lose the drop for that turn. Mixing up your targeting — occasionally going for the other slot — keeps the opponent honest.
Tips & strategy
The Intimidate + Lunge stack is one of the cleanest tools for neutering a physical core. Get a partner with Intimidate in the lead, and now Lunge takes the same target from -1 to -2, effectively halving their Attack output.
Lunge is especially valuable in Trick Room matchups where the opposing team runs heavy, slow physical attackers — precisely the targets you want to debuff before they can move.
One firm limitation: Lunge cannot hit Ghost-types. If the opponent's physical threat happens to be Ghost-type, you need a different answer.