Might be my mature vision but that looks like a root growing up the current flower spike. As for trimming, you can cut anywhere from just removing individual spent flowers all the way down to removing the entire old spike. I usually just remove individual flowers and see what the spike does.

tj

I cut it off completely to the base. Your plant will make a new spike of flowers in the Fall/winter.

Jane

I would leave the stem as long as it's still green. Many phals will put put branches on the old stem, and bloom from the branches..it won't stop your Phal. from putting out a new spike at all. If it's green, it can rebloom on that spike, if it turns brown, then you cut it.

Thank you all! The spike ended up turning brown and I cut it! Now it's putting out a new leaf - I'm anxiously awaiting a new spike 🤞