How rare is this 'pokemon card'?

i found this box at my school titled: dear stranger, happy birthday. and in the box was hundreds of playing, pokemon, yugioh, dragon ball z and harry potter cards and i found this one quite weird. it's holographic on both sides and i think it's a mew pokemon card, but doesn't look like one, what do you think? a href="http://s928.photobucket.com/albums/ad123/slippeo/?action=view¤t=Ancient_Mew_Card_by_CloakedRanger.jpg" rel="nofollow"http://s928.photobucket.com/albums/ad123…/a