Alice is the secondary Love Interest of Sam Witwicky in Transformers: Revenge of the Fallen and she is really a Decepticon assassin in human form. She is played by Australian actress, Isabel Lucas.
She was a Decepticon spy Megatron, disguised in human form, and had installed to Spy on Sam Witwicky.
At the university, rumours spread amongst the boys that Alice was sexy, and Leo especially took a liking to her because he was single and Leo believed Sam was cheating on Mikaela by lusting after Alice.
Several times Leo fell out with Sam over Alice. One time Alice went to a night party with Sam with her naked shoulders glimmering in her green dress. Also, at the party when she wanted to kiss Sam, Bumblebee, in his car form, began honking his horn wildly. Some guys asked Sam if it was his car, Sam said he'd get it out of there. Unfortunately Alice followed, saying she loved Cameros, and she forcibly got in with Sam. After some awkward flirting Bumblebee realized this was a Decepticon he was carrying and vomited green goo on Alice, who stomped off.
Afterwards, Alice was next seen marching down the hallway with Leo who asked her if she liked pizza and if she was vegetarian or not. Alice just asked where Sam was and came in. In Sam's room, he had gone cray-cray and was scribbling Cybertronian symbols all round the walls. He then rambled on about science and mathematics and then said 'OK, what were you saying?' Leo believed Alice was embarrassed but he was wrong, he didn't know Alice liked Sam's weirdness. So Alice got horny, approached Sam, and rudely shoved Leo out the door.
This turned out to be a good thing for Leo though as Alice slammed Sam against the wall, saying how horny she was, and then she threw him on bed and made out with him, kissing him, and then she extended a stinger to kill Sam, but then Mikaela came in. Mikaela saw Alice and Sam kissing and dumped Sam but then when Sam went for Mikaela, Alice strangled him. Mikaela came back and saw the robot, then she saved Sam and they found Leo and fled. Alice was rampaging through the campus in her robot form firing guns and stuff. Eventually she marched outside after them and took on her Alice form again. Then she was about to saw in through the car but Mikaela ran her over.