Robo-Smash: Slams his dual telephone poles on the ground, doing electrical damage.
Robo Charge Smash: Similar to Gargantuar's Charge Slam, The Mech zooms towards the Player with its rocket feet, and does an extremely damaging smash.
Pulse Shots: fires a burst of 3 electric shots at the player.
Time Bomb: Fires a bomb at the Player that takes 4 seconds to explode, and deals around 30 damage.
Health
Easy: 1400 HP
Normal: 2000 HP
Hard: 2600 HP
CRAAAAZY: 3200 HP
Super Robot Wave
When the boss slots land on 3 Mech Gargantuar icons in Garden Ops, a Super Robot Wave will occur. Robo-Zombies replace all zombies in the wave, with some Zombie Heroes being replaced by customized Tank Commanders and default or customized Computer Scientists.
Strategies
The Mech Gargantuar has similarities to both the Gargantuar and Giga-Gargantuar. Similar to the Gargantuar, he can quickly rush towards you and slam the ground, and like the Giga-Gargantuar, his ranged attacks and slam have electrical properties. Try to attack when the Mech is about to launch a bomb; Although it does more damage, it takes a long time to explode, and the Mech remains idle while doing this. Use similar tactics as you would the Gargantuar, however, keep in mind that the Mech is completely armored, and takes very little damage when shot at. Always aim for the head: It's not only unarmored, attacks also do critical damage.
On a Super Robot Wave, this can either be a real challenging wave or an extremely hard wave, depending on the difficulty. This is also mainly due to the bunches of Robo-Zombies and Computer Scientists that will back Mech-Gargantuars up. If you can get on something, like a rooftop, or some elevated ground where they cannot reach you, then you should be ok and try to rain your firepower on all of them, like a Gargantuar Wave. Peashooters and Corns are the best for this. But if you do get on something, beware that they will ALL be shooting at you.
The best thing to do, is to try and take out all the Robo-Zombies and Computer Scientists before taking on the bosses, if you can. This can be extremely hard and challenging if you're doing this on CRAZY difficulty because the Robo-Zombies will have so much increased HP. In fact, a group of them can survive a full blow up from a Sombrero Bean Bomb or Bigger Better Butter and they will STILL be running. If you're playing as a Cactus, you can corn-strike a group of them out as they spawn, as the boss wave starts. Sunflowers and Roses will have harder times surviving (unless you're Vampire Flower), due to their health. Citrons are slow movers but can use their ball-form to escape but beware that the bosses and robots will be tracking their way to you real fast! Torchwood is pretty tanky and can take lots of damage but they move slow, so try to stick close to a Sunflower.
On Easy/Normal and even Hard difficulties, this Super Boss Wave can be challenging. On CRAZY difficulty, this would be the SECOND hardest Super Boss Wave, seconded to the Super Yeti Wave, and this is due to the increased health the Robo-Zombies will have and that can severely overwhelm your team really quickly. Stick close to the Sunflowers and but also try to not stick together with your teammates as Mech-Gargantuars have increased melee attack power when they slam on the ground.
However, unlike in Plants vs. Zombies 2, it does not shoot lasers from its eyes, nor can it be completely stunned by the EMPeach like in said game.
When the Mech Gargantuar takes damage, a voice can be heard from the Imp piloting it.
The sounds the playable Imp class makes when hurt is audible alongside new audio cues
This is the third Zombie boss to not have a ragdoll mode when vanquished, the others being the Yeti Zombie and the Treasure Yeti.
Coincidentally, all three of these bosses are actually robots (not including the Imp inside the Mech Gargantuar).
Sometimes when he is vanquished, he won't explode and pieces of him will not appear. This is a glitch that sometimes occurs with the Yeti Zombie boss as well.
The Imp inside of the Mech Gargantuar appears to be smaller than the Imp class, for unknown reasons.
It also shares this trait with the regular Exploding Imp, as the Imp on top of the bomb is much smaller than the Imp class or the similar Exploding Imp Fan.
Despite being robotic, this zombie is not stunned for longer than usual by the Citron'sEMPeach.
However, this may be because this zombie is a boss, and zombie bosses cannot be Goatified.
Although the Gargantuar Prime in Plants vs. Zombies 2, the zombie that this is based on, launches Bug Bot Imps (which is what the Future Imp is based on) from his back, the Mech Gargantuar instead fires a bomb from his back in Garden Warfare 2.
It is unknown why this is, as the regular Gargantuar in the Garden Warfare franchise fires an Exploding Imp from him back, and the Future Imp even has a self-destruct attack normally.