Guroro the Iguanodon was the first in a special breed of enhance Dinosaurs, who appear in Ep.17 - "Fear! Izen has Melted!" - of Dinosaur Great War Izenborg as the 29th Monster in the show's order of appearance.

_Bio and Abilities_

Much like the other dinosaurs before him, Guroro was sent out to attack the surface world, emerging from the sea, a rarity showed by most land based dinosaurs, making it the 2nd Aquatic agent after Parasa; had the ability of eye laser beams, breath fire, as well release an acidic spit, which he would control mentally and guide it around up through any structure, proceeding to melt these down – the acid was stored on massive sacks glands on the sides of the neck. He was among the few Dinosaurs capable of Speech.

_Story_

Guroro emerged near the Tokyo Docks and began to cause destruction by spewing an acidic spit he could guide mentally – with buildings and bypasses breaking apart. In the chaos he was photograph by a bystander and D-Squadron is put on notice, as they are concern the attack happened close to the site of a Rocket Power Military Blimp.

Quick Rant: why would there be the need of a Rocket Power Blimp in a world where there are Flying carriers and Super Tanks?

Just Saying!!

Also; this thing is a Rocket Power (Nuclear?) Blimp – reactor and all – and yet it uses a Propeller to move forward; you'd think three rockets thrusters would be enough. You may facepalm from this point forward.

The next day, the JSDF and the Izens ramp up security around the launch, but Guroro reappears and spits its acid towards the blimp, killing one guard in the process; As the Blimp Launches, Guroro launches its attack, which the IzensUnits and the JSDF responds to; Meanwhile, the acid begins to wreak havoc in the airship, melting crew members, and the vessel crashes, exploding on impact (Oh the Humanity! - The Folly of it all!). Guroro then challenges/threatens to do the same to the Izenborg and disappears in a cloud of smoke.

After much conversation between Torii and Zen, the Izenborg appears on the docks, where Guroro releases is acid and guides it to the Tank, melting it, to the horror of Ai, Barra and Ippei. As Ururu and Guroro celebrate, the Transport Plane shows up, lowering the real Izenborg tank with Zen in it, revealing the other having been a fake; the Pilots board it and take their battle to Guroro, with IzenTwo dealing with the Acid.

In the battle, IzenTwo is contaminated by the Acid; IzenOne tries to cool the melting process with the freeze ray, but it fails and the 2nd Unit crashes; Guroro tries to go after it, but is stop by an electric net fired by IzenOne, though to no avail. IzenOne fires a harpoon with a Balloon that lifts the Beast into the air, and is then shutdown by rockets from IzenOne. The Siblings then IzenCross and Super Izenborg takes to the sky to finish off the beast; However, the Super Izenborg is also covered in the Acid, making some of its weapons malfunction. Izenborg goes full speed (Izen Max Fire, is what Zen shouts, I think?) and rips through Guroro – the monster explodes; A flustered Ururu melts down after another defeat.