And I'll cross oceans like never before - sirona - The Avengers (2012) [Archive of Our Own]

http://archiveofourown.org/works/360893



'Oh, hell no,' he thinks, looking down at his hands only to be met with furry paws instead of the fingers he expects. --Or the one where Loki turns Clint into a puppy, and his new condition allows him to gain some startling insights into their resident babysitter agent.