Commission for Ankaru.

Spike has long been Twilight Sparkle's Number One Assistant, and a helpful hand to all ponies in Ponyville. But he longs to be something more, to feel like an equal, something more than, for example, the babysitter's helper when no one else is available.
But when a camping trip with Marina the Changeling, her partner Moonbeam, and the Cutie Mark Crusaders goes wrong and the CMC are kidnapped by a group of vengeful Diamond Dogs, Spike is given the chance to show what he's truly capable of as he seeks to follow Marina in pursuit of the kidnappers, determined to help her save the young ponies. As his mettle is tested, however, he might discover he is not as strong or as capable as once thought he was, and that his actions may have terrible consequences for the ponies he only ever intended to help.