Goosebumps (1995)

S1E4 The Girl Who Cried Monster

Lucy has a knack for spinning monster tales, but she's shared so many that her friends and family can’t stand to hear another. One day, she stumbles upon a genuine monster: the librarian overseeing the summer reading program. Unfortunately for Lucy, her endless fabrications have left everyone skeptical of her claims. To make matters worse, the monster is aware of Lucy and seems to have her in its sights.