Mouse in apartment, help??

Since cats and traps have already been suggested, here's a method I've used successfully. Get a spoon, some peanut butter, and a large shoe. Put the pb on the spoon and place it about 6 inches from what you think the mouse is under. Stand very still over the spoon with the shoe poised in spider-killing position. Mice are very curious and not too bright...just don't move. When it comes to get the peanut butter, WHAP!! The mouse will bounce about a foot in the air and scare the hell out of you, but scream like a little girl and hit it again. And again. Put dead mouse in plastic bag and dispose of, then clean up the peanut butter that is by now spattered around the room. Go get a shot of whiskey to get rid of your heebie jeebies. Works every time!!

[Los Feliz Slim]

Here's your real problem: where there is one mouse, there are undoubtedly more. In your walls, under your floorboards, in your ceiling. Like, hundreds. Crawling all over you while you sleep. Until you address the various access points that mouse nation has into your apartment, you'll never be safe.

[CORed]

If you saw one mouse; most likely there are several in the apartment. Your options are traps, poison or a cat.