Invincible from the Dream: The Door of Dreams

On the train to college, Fan Tian is struck on the forehead by a 'meteor' and gains the 'Door of Dreams'. Every night after falling asleep, he can choose to enter a random dream world or an unlocked dream world. Dream worlds include: martial arts, xianxia, apocalypse, sci-fi, urban supernatural, mythology, etc. Dying in a dream forces awakening, with no physical injury but mental fatigue. Skills, martial arts, and knowledge gained in dreams can be brought back to reality (requiring proficiency to digest); items can be brought back but are limited by the 'reality containment cap' (preventing directly moving a nuclear bomb back to reality); attribute points (physique, spirit, agility) can be partially brought back, with spirit prioritized. The duration of sleep in reality determines dream duration: 1 hour in reality ≈ 6 hours in dreams (can be extended with increased spirit). Special mechanism: entering the same dream world for seven consecutive days triggers 'dream fusion', where that world's rules begin to subtly affect reality. As strength increases, he can later pull others into dreams (a major trump card). — Description from novelcodex.org