The Lock Card is not dangerous, but it's not friendly either. This card likes to lock people up! Eeek! Sakura, Li, Meilin, and Madison faced Lock's power in Episode 38. It takes on the form of a gold and green colored lock that can float.
After trying to pull the door open, Sakura figured out she could use the Key of Clow to open it. However, when she tried, Lock's form appeared and pulled the key out. Li used one of his Ofuda's to stop it from locking them in the room forever, which allowed Sakura to seal it. When summoned, it creates a lock on whatever is commanded.
