Near the start of the trailer, there is a small worm-like tentacle with spikes on the front of what might be it's face, possibly teeth. There are also spikes on it's chest. it is unknown whether it is a different creature or a variation of the Unknown Tentacle Demon. The creature may be able to fly as it floats/slithers off to the top of the screen.
Later in the trailer, it can be seen wrapped around a support pillar, it crushes the pillar like a snake. There are several larger Unknown Tentacle Demons wrapped around a bulding, the tentacles appear to be coming from one large mass, so the full creature may resemble a squid. The tentacles move around and destroy parts of the building as they move in what it seems "terraforming" the landscape into a hellish habitat for the invading demons.
There are also Smaller ones as shown here that are shown in the new E3 Doom eternal demo, they have very low Health.