Is an Enchantment Creature also an Enchanted Creature?
In addition to the answer you've already gotten, I want to point out that Spiteful Returned doesn't say 'another enchanted creature'; it specifically uses the phrasing 'when enchanted creature attacks'.  This refers to the creature that Spiteful Returned is enchanting, and that creature only; if you have Spiteful Returned in play and, say, a Bloodcrazed Hoplite that has a Hopeful Eidolon bestowed onto it, then attacking with the Bloodcrazed Hoplite won't trigger Spiteful Returned's ability.