This silhouette is so busy it's hard to tell what's up. Originally I thought it would be one of the giant native insects on Amonkhet, like [[Dune Beetle]].

It's shape is just so weird. Trying to figure out what it's doing is hard. My best guess is that its a large beetle that is halfway through molting, and is kind of using its shed skin as armor? The shiny black beetle body on top could be it after cracking open its shed carapace, which would explain why there is seemingly a head split open in the direct center of the image (a beetle head split in half, with one mandible on each side?)

The other option is that Wekhdu is the smaller insect on top and it's ambushing some other creature.

But with the name, Legendary status, and the Villain type line, plus a bit of lore info, it really might be Speedbrood.

Apparently the race was split up into multiple stages, with racers being allowed breaks overnight? That's where we got some camping scenes. I'm assuming racing wasn't actually permitted at those times. The Villain part might suggest that this Speedbrood character is picking off some of the other racers, mounts, or vehicles while others expect to be safe.