Summary:
The destroyed Fear of Abduction took my Creature with it into the graveyard instead of giving it back to me!

Visible Indicators:
As you can see on the picture, if you zoom in on the graveyard then you can see that my sweet little Crab is still attached to it. Now also take a close look at my hand. You might notice that i actually hold two cards here, my land and an invisible Crab. I can hover over the invisible card and it will highlight my blue land (indicates that i can cast the card) but i cant actually play the card, so that is more than a pure visible bug =(

Hint:
I used the 5 CMC Red Removal Spell that also exiles the top card from my library for future play. That probably caused the trouble!