The equipped monster loses 1000 ATK, but it can attack your opponent directly.
Rulings
Individual Card FAQs
"Shooting Star Bow - Ceal" decreases the current ATK. So if "Injection Fairy Lily" is equipped with "Shooting Star Bow - Ceal" and activates her effect, her ATK is 2400 ((400 - 1000) + 3000 = 2400).
If a monster equipped with "Shooting Star Bow - Ceal" declares a direct attack, and "Shooting Star Bow - Ceal" is removed from the monster during the Battle Step with "Mystical Space Typhoon" or "Tailor of the Fickle", the monster is no longer capable of attacking directly and a replay occurs.
"Tyrant Dragon" must attack a monster in order to gain its second attack, so if it is equipped with "Shooting Star Bow - Ceal" and attacks directly, it cannot get a second attack. But "Tyrant Dragon" equipped with "Shooting Star Bow - Ceal" can attack a monster, and then attack directly.
Netrep Q&As
Q: Would equipping “Shooting Star Bow – Ceal” on a fusion summoned with Magical Scientist allow it to attack directly? A: A monster that is Special Summoned via “Magical Scientist's” effect... cannot attack the opponent directly. Even equipping the Fusion monster with “Shooting Star Bow – Ceal” won't change that condition. Steve Okegawa, 12/18/2003
Spell|
Equip