These are some rough pencil-sketches of ideas for villains & monsters for my crossover idea "Combo-Ninos, Robotboy & Yin Yang Yo! Monsters all out Attack".

This includes the following:
The Ballroids, bowling-ball like alien robots.
Twisted hellish versions of "Angels.
Racker, an insectoid Shadowkan mutant with rake-like claws.
Some random monsters from the Insect-World (included here are the Falcon-Fly, a swarm of Parasite-Bugs and a huge and powerful Crab-Crusher).
The Mutating Man, a shape-shifting supervillain based on the little known DC-comic character, Animal-Vegetable-Mineral Man.
the Penanggalans, a very strange breed of vampires from Malaysian folklore (who are from the "Horror-World").
The Fallen, an evil fallen angel with dreams of taking over the world.
Owl, a bird-like humanoid based on the Owl Imagin (from Kamen Rider Den-O).