The Worm Turns?

Researchers have discovered 20m year old fossils of giant 2m long burrows in sandstone in Taiwan (https://www.theguardian.com/science/2021/jan/21/giant-worm-undersea-lair-discovered-fossil-hunters-taiwan). After considering many options, they have concluded that the burrows were once occupied by enormous versions of Bobbit worms (Eunice aphroditois). These soft-bodied worms have powerful jaws and ambush marine creatures that swim by their burrows, pulling their victims (e.g. fish) down into the sands. The burrows of these worms are strengthened with mucus but the entrances have to be replaced after each attack. This produces a 'feathered' pattern, like that seen in the fossils. So, once, the early worm could catch the 'bird'.