When audiences first heard Admiral Ackbar's "It's a trap!" line, few would have predicted how large of a pop culture touchstone it would become. Decades later, it's pretty clear just how much the iconic line has transcended the Star Wars universe, appearing in shows like The Daily Show, The Colbert Report and Family Guy.
In 1983's Return of the Jedi, the Rebels got wind of secret plans for a second Death Star and engaged the Empire in the Battle of Endor. Han Solo's strike team came to the moon's surface to destroy the weapon's shield generator, with Ackbar's fleet stationed in space, waiting to shoot down the Death Star. However, Ackbar quickly realized the Empire was ready for them as Tie Fighters began attacking, and that it was indeed a trap orchestrated to snuff out the Rebel Alliance. Ackbar, Han, Lando Calrissian and the Rebels would eventually triumph though, helping Luke Skywalker end the current Sith reign.
In Darth Vader #15, Charles Soule and Giuseppe Camuncoli turn back the clocks, shaping a story set years before that fight. Even better, it's a tale in which Ackbar actually lays down a trap of his own for the Empire.
At the end of the last issue, with Darth Vader and his forces seeking to strengthen Palpatine's grip on the aquatic planet of Mon Cala, Ackbar's unit sent their leviathans up from the depths of the ocean to flood King Lee-Char's headquarters. Issue #15 picks up with the flooded kingdom in a state of turmoil and Vader plunging to the sea floor. As a result, Grand Moff Tarkin instructs Colonel Bergon's Skybase (basically the Empire's version of a helicarrier) to descend to the surface and try to find the king, as well as survivors such as Vader and his crew of assassins.
However, this was all part of a bigger, more intricate trap laid down by Ackbar. We see him on the front-lines leading a deep-sea unit to attack the Skybase. They get within distance and fire a swarm of missiles at their enemies. Bergon plays off the attack, believing their energy shields will stop the missiles, but somehow the shields are penetrated and the entire ship blows up. As Tarkin inquires about the loss, it's revealed that the missiles were metal-cased as opposed to being energy projectiles. This prevented them from being deflected, and allowed them to get through the shields. Ackbar simply needed to get closer to ensure that the barrage of missiles would be able to hit the Skybase in full and that's the reason why they flooded the king's headquarters -- to get the Skybase to come down to the surface, thus closing the distance and putting them in range.
It's a deft move .and one which shows Ackbar's prowess, not just as a military strategist, but as a leader who's fearlessly willing to head into the field with his soldiers -- something that even Tarkin expresses surprise at. It's a mixed bag of emotions for him as he's quite upset his Skybase got duped so easily. So much so that he berates one of the heads of security and technology, Commander Jordo, who was responsible for ensuring the Skybase would be invulnerable. For his failures, Tarkin demotes Jordo to the rank of Stormtrooper and sends him down to the planet to fight on the ground.
Clearly Ackbar's plan has rattled the Empire's cages, making Tarkin regret how badly he underestimated his opponents. Sadly though, while Ackbar's assault was effective, it's merely a temporary success because Tarkin now decides that this attack is officially an act of war against the Empire. The issue ends with him instructing his men that "escalation" will be the response, as we see a few Star Destroyers entering the planet's orbit. So unless Ackbar has another ace up his sleeves, it seems that Mon Cala's resistance may finally be running out of time.