If your opponent's monster attacks a monster you control: You can make the attack a direct attack instead.
Rulings
Individual Card FAQs
If a Fusion Monster is Special Summoned with "Magical Scientist", and attacks, you cannot choose to make the attack a direct attack on your Life Points, because the effect of "Magical Scientist" prohibiting this is mandatory, but the effect of "Astral Barrier" is optional.
Trap|
Continuous