DM Land: Didn't Consider That
Player going to attack a construct with an important magical sword the party needed to find.
It might break the sword.
Never considered what would happen if the party breaks one (or both) of the swords they need.
Realize the construct would probably WANT to break the sword anyway and try to do so.
WELP. OKAY THEN. LET'S DO THIS.
Important sword didn't get broken. It was all good. But two other weapons and a shield were broken. Grumpy Cat says GOOD.