Given the task definition and input, reply with output. In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: In the Sonoran Desert, French scientist, speaker at the Montsoreau conference, Claude Lacombe and his American interpreter, cartographer David Laughlin, along with other government scientific researchers, discover Flight 19, a squadron of Grumman TBM Avengers that disappeared more than 30 years earlier in the Bermuda Triangle. The planes are intact and operational, but there is no sign of the pilots. An old man who witnessed the event claimed that "the sun came out at night, and sang to him". At an air traffic control center in Indianapolis, controllers listen as two airline flights narrowly avoid a mid-air collision with an unidentified flying object, which neither pilot chooses to report, even when invited to do so. In Muncie, Indiana, 3-year-old Barry Guiler is awakened in the night when his toys start operating on their own. Fascinated, he gets out of bed and discovers something or someone (off-screen) in the kitchen. He runs outside, forcing his mother, Jillian, to chase after him.
Investigating one of a series of large-scale power outages, Indiana electrical lineman Roy Neary experiences a close encounter with a UFO, when it flies over his truck and lightly burns the side of his face with its bright lights. Chasing it, he almost hits Barry and Jillian, and they encounter the UFO with three other UFOs. Neary joins three police cars pursuing them, but the spacecraft fly off into the night sky. Roy becomes fascinated by UFOs, much to the dismay of his wife, Ronnie. He also becomes increasingly obsessed with subliminal, mental images of a mountain-like shape and begins to make models of it. Jillian also becomes obsessed with sketching a unique-looking mountain. Soon after, she is terrorized in her home by a UFO which descends from the clouds. The presence of the UFO energy field makes every appliance in Jillian's house malfunction and Barry is abducted by unseen beings.
Who does Jillian chase?