is it undead

[Le Slayer]

is the Ankou undead as in can i cast crumble undead on it

[Chewy]

umm ... yes you can i be;live bcause crumble of undead works on zombie , ghosts , and skeletons .... and its a skeleton i think

[Bacon]

http://www.runehq.com/RHQMonsterView.php?id=653

Try looking for your answer next time :D