Ripiphorus beetles. Rare bee nest parasites with room for new research and undescribed species. Rather than retelling my encounters, here are previous comments I left on the subject:
What is your Favorite Lifer from this week? - Nature Talk - iNaturalist Community Forum
“Like Finding a Unicorn” - Nature Talk - iNaturalist Community Forum
Random Nature Encounters and Stories - Nature Talk - iNaturalist Community Forum