Bug: Splash potions will clip through a player if the player jumps, with an acceptable time window.

Step by Step:

• Prepare any kind of splash potion
• Pillar up 2-3 blocks and stand in the corner (not necessary, but will allow you to see the effect better)
• Throw the potion while looking straight vertical, and as it starts to fall, jump.

If done correctly with the timing showed in the video attachment, the potion will clip through the player.