Day 29 of KaiJuly and the final part of Mechanical Mayhem...

U-Killersaurus

Height: 79 meters

Weight: 82,000 tons

First Appearance: Ultraman Mebius & the Ultra Brothers

History: U-Killersaurus was first seen fighting against the Ultra Brothers; Ace, Ultraman, Ultraseven, and Jack on the Moon. However, U-Killersaurus is able to overpower the four Ultra Brothers with its strength. When the Ultra Brothers combined their beams into one, U-Killersaurus takes flight and dodges their combination beam and flys towards the Earth. While fighting on space, as the Ultras tried to use their Ultra Beams, Ultraman warned them if it misses, it will directly hit Earth. As a result, U-Killersaurus took the chance and grab the Ultras with his tentacles until Ultraman uses his Ultra-Slash to free them. After Ultraman and Seven weakened the Terrible-Monster, Ace and Jack blast it down towards the sea of Earth with their Metallium Ray and Specium Ray respectively. The four Ultra Brothers then sealed Yapool and U-Killersaurus with their Final Cross Shield. Twenty years
later, the seal of U-Killersaurus become undone thanks to Alien Guts and Alien Nackle. Yapool revived as well, later U-Killersaurus killed Alien Nackle, which is supposedly their ally but Yapool revealed they are nothing than just pawns. The Terrible-Monster then proceeds to evolve into U-Killersaurus and overpowers the Ultra Brothers and Mebius. Until Taro and Zoffy arrival to restore the energies of the Ultras, they managed to fight on par with the Terrible-Monster by using their beams and slash attacks. When Mebius about to use his Mebium Shoot, the Terrible-Monster (Yapool) shows that he held Aya hostages and then blasted the latter with his Killer Eye Ray and holding Mebius on the ground with mandibles and prepares to use his ultimate attack on Mebius. Though suceeded in using his ultimate attack, the Ultra Brothers then fuses with Mebius and transforms into Mebius Infinity.
U-Killersaurus Neo then crumbled to dust after Mebius Infinity uses his Cosmos Miracle Attack and dashing into his body and saving Aya.

Trivia: According to the final cutscene of Ultraman Fighting Evolution 0, its full name is Ultra-Killersaurus

https://www.deviantart.com/cybereman2099/art/KaiJuly-U-Killersaurus-850287949