When you put a Strider on a lead and drag it somewhere, afterwards the Strider will refuse to move from the spot it is in. It will literally just stay there until the end of time.
That is until you pull out a Warped Fungus or drag it with a lead once more.

Steps to reproduce

1.  Find a Strider hanging out in lava
2. Use a lead to drag it somewhere else
3. Notice how it doesn't move on it's own and never will, no matter how long you leave it for