Decoy Queen

The Decoy Queen was a alien queen from Ben 10 Alien Swarm movie & main antagonist of this film

The Decoy Queen uses the body of Victor Validus as her host. Validus discovers he had been infected by the alien chips and secretly starts studying other Nanochips found by thePlumbers. However he was caught removing them from the Vault and is accused of stealing them by Max. Validus tries to warn Max about the Nanochips, but Max doesn't believe him and expels Victor from The Plumbers.

Validus keeps on studying the nanochips (which are actually members of the Hive), until he is completely taken over by the Queen. The Queen uses the Hive Chips to infect human hosts and plans to take over the entire planet.

However her plan is thwarted by Elena, Gwen, Kevin and Ben (in the form of his new alien, Nanomech). Even though she tries to control Nanomech, she is unable to do so as Nanomech is still half-human (because the chips can adapt and humans never give up, according to Ben, since that's what Ben said just before he killed her). She put up a brutal fight but in the end, the Queen is killed by Nanomech's bio-electric blast. With their Queen destroyed, the Hive quickly dies, freeing their victims and ending their threat.

In Revenge of the Swarm, it was revealed Elena is the real queen of the Hive all along (the Queen in Alien Swarm was just a decoy produced so that Ben wouldn't suspect her) in which she tried to keep Ben away from Julie Yamamoto in order to keep Ben all to herself. Ultimately, when she used the drones in an attempt to choke Ben to death, she was convinced by Julie to stop all this if she really loved Ben and at that moment Elena took control and sacrificed herself.