How do you get the blue anomaly in Animal Hospital away from the window?

There are two reliable ways to clear the creature from the window:

Method 1: Offer Coffee - Make a cup of coffee and offer it to the creature. If you use a fresh, untouched cup, take two sips yourself so you don't waste the sanity recovery, then hand the cup over. It will calm down and leave.

Method 2: Close the Shutters - Alternatively, close the shutters when it rears back to hit the glass. The window may crack, but the creature disappears and moves on. Closing the shutters is always free, whether you were right or wrong.