Mondo comes from a far, far galaxy, part of an alien species called Umbras. Those aliens are fucking huge living black holes. Teir skin is so dark it absorbs all light.
Mondo is the biggest of all. With his 2000 ft height, he sure doesn't come unnoticed.
He developed a certain passion for buildings and architecture. When he doesn't builds stuff on his home planet, he gives a hand to other species. At his size, construction work is like making small models. To make things better, he lost an arm while saving Earth from an asteroid and now uses a handmade prosthesis, which greatly increases his rate of work.
Oh, and in his 1028 years of existence, no, he never stepped on anyone.