Tools with Siphon in offhand apply the Siphon mechanics to non-Siphon tools in your main hand.

My user is bwiley45. For some reason, I found a bug that applied Siphon to my shovel (which doesn’t have Siphon) while holding another tool that had Siphon on it in my offhand. I’m showing this in the video. (I’m using a modpack that’s why it looks different, but I don’t think it has to do with the modpack itself)