Strange Mongo query


I see this in my Kadira dashboard:
fetch on 17604ms

coll :
selector : {"ns":{"$regex":"^meteor_db\\."},"$or":[{"op":{"$in":["i","u","d"]}},{"op":"c","o.drop":{"$exists":true}},{"op":"c","o.dropDatabase":1}]}
func : fetch
cursor : true
fields : {"ts":1}
sort : {"$natural":-1}
limit : 1
docsFetched : 1
docSize : 28

It’s from the login method. I have no idea what this is, why it took over 17 seconds to complete and why there’s a dropDatabase line. Any ideas?