“ Adventurers are to capture an unknown monster for examination (for a sage or wizard) but they are themselves captured by the monsters, and researched.”
“ Dust Elemental
https://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=1594
At the corner of air and earth elemental planes resides the dust Elemental, a growing threat to Parisia. With it's powerful choking attack, this creature is a threat to the city. More and more of them are appearing in town, spawned from the many dust devils, a frequent foe of the party, they come in size from 3 HD to 20 HD. Why are there so many? Why in the city?”