Pachycephalosaurids
Added 2022-06-22 18:00:04 +0000 UTCI think the modern consensus is that Dracorex and Stygimoloch were just juvenile Pachycephalosauruses before its skull gets chonky enough to swallow all the spikes, but the names are too cool not to use.
These are those dinos with 9-inch thick skulls that are always head-butting each other in illustrations, but probably just had it for sexual display or at best bonking their heads into other dino's soft parts. This is D&D, though, and we're not going have a Pachycephalosaur that doesn't head-butt things, because sometimes whether things feel true is more important than whether they are. I compromised and had it ram flanks instead of head-on collisions, though.