Kalista Channel

When Kalista uses her black spear on someone after her animation finishes she can actually click on the black spear to do the Oathsworn's channel animation on it. (You do the initial cast animation on someone, they fall over dead, then you click on the spear and channel on it too) Additionally if you are in the middle of channeling on the black spear when it disappears you continue to do the channel animation until either a move, ability, or aa command is input.

To recreate just use your black spear on a target and after your initial cast animation finishes click on the spear in the same way the recipient would.

It doesn't seem to have any negative effect but it is kind of strange to be able to do.