The Gargantuar's main attack is smashing his telephone pole in front of the player. Beware, as it can deal high damage and has splash damage as well. Also, beware that, if he roars, he will charge straight at the player and smash them. Although easy to dodge, other zombies will use this as an opportunity to attack. When Gargantuar bends down, he fires an Explosive Imp at the player, dealing high splash damage. Due to his size, he cannot be swallowed by a Chomper, rendering them semi-useless. The Gargantuar cannot be frozen, however he is not immune to the Chomper's Goop, which will slow him down and make him easier to vanquish.
Gargantuar Slam: Smashes a plant with his pole.
Pole Charge: Rams at the player and attacks with a stronger smash.
Gargantuar Imp: Launches the Exploding Imp from a medium distance.
▲ All Gargantuar melees have increased in effectiveness.
Super Gargantuar Wave cutscene
When the slots land on three Gargantuars, an animation will show with a hand smashing out of the ground holding an Imp. The Imp then looks around while making small "eh?" noises. Suddenly, the Gargantuar unearths himself, roaring loudly. He then calms himself, stroking the Imp (which the Imp appears to enjoy) before putting him in his trash can. He then grabs his telephone pole from the ground, looking around wildly (presumably to search for plants/brains). The cutscene ends and the boss fight begins. During a Super Gargantuar Wave, Exploding Imps and Blitzers will appear often.
Gargantuar with other zombies on a stone mural
A Gargantuar in Plants vs. Zombies: Garden Warfare 2.