I'd leave it

You have a pup, congratulations. It's fast growth is going to amaze you.

Laurie is right, it's a pup. Just leave it alone and it will grow into another leaf. Many Sansevierias grow by spreading rhizomes under the soil. When they are ready, a new leaf breaks through the soil and it is called a pup until it grows into a new leaf.

Thanks for the responses! I’ve had a few new growths over the summer. This one (photo attached) just sprung from the soil in the last month of summer. So this is what the pup will turn into when it grows a new leaf?

I actually did not repot the snake plant when I bought it about a year ago, so it’s still sitting in the liner it came in. Would anyone suggest I move it into a bigger one? The pup seems crammed but I’m not sure if that’s just how they grow.

My Sans generally do better when they are cramped, not to the point of becoming totally root bound, but pleasantly cramped. A Sans that grows via rhizomes can easily break a plastic growers pot, just split it on the side. So -- you don't HAVE TO repot right now. Also, winter isn't the best season to do so. But you may want to give your Sans a repot in the spring when growing season begins. Just make sure to use a pot with sufficient drainage holes (I always prefer more than one), a gritty and fast-draining kind of mix (I add perlite AND pumice, or pumice and chicken grit, to C/S soil), and consider using a plastic pot so the Sans can break through it in the future.

I have a plant that puts out pups this way every time. After a few months the pup will suddenly stand upright and start spreading its leaves.

I had one grow out of the bottom drain hole and grew about 5 inches before it started it's upward action. It wants to get as far away from it's competition for light as possible.