Simian

Simian is a character introduced in second season of Ben 10: Alien Force, an Arachnichimp(Spidermonkey's species) from Aranhaschimmia. He first appeared in Birds of a Feather, which was, so far, his only appearance.

History
Simian appeared for the first time in Birds of a Feather, where, coming on Earth, he met Ben(as Spidermonkey), Gwen and Kevin being attacked by a group of DNAliens. Mistaking Spidermonkey for a true Arachnichimp, Simion interfered in the fight and forced the DNAliens to leave, saving the group. When learning he had actually saved "Ben 10" and his team, he decline their offer to join their team to fight DNAliens, stating he couldn't. He also said that he didn't know anything about DNAliens.

Later however, Ben surprised him when he was stealing equipment from a cryogenics lab. He helped him to escape as Goop, but asked for an explanation. Simian then replied he was the Prince of Aranhscimmia, and, to prove he was a valuable king, had to get and bring back on his planet a crystal from a base on Earth's moon. Feeling empathy for him, Ben decided to help him, and convinced reluctant Gwen and Kevin to come too.

Arrived on moon, the group successfully passed through the base's defenses, even being crushed before spraying the acid on the floor, but Ben started having doubts about Simian's motivations when the Arachnichimp asked him to attack Lu, the harmless guard of the base, and tried to kill him himself when Ben refused. It was eventually revealed that Simian had lied to Ben, and was actually a mercenary hired by a Highbreed to steal the crystal, which was the power source of a communication base needed by the Plumbers to protect Earth from the inevitable Highbreed invasion. He pushed Kevin aside when he made his escape.

Ben later stated that he fully doubted Simian when he mentioned the DNAlien's acid, because Simian said he had no idea who DNAliens were.

When bringing the crystal back to his client, Simian realized too late that Ben had replaced the crystal inside the container with a DNAlien ear cleaner filled with worthless but powerful alien acid. Thinking this was a bad joke from Simian, the Highbreed chased after Simian and seemingly killed him off-screen with the acid as his tortured monkey sounds were heard.

Power & Abilities
Like Arachnichimp, He has super agility,can stick to walls,can spin webs,can shoot webs from his tail,he also very skill in hand to hand combat.