Solid State Logic | Halloween Freeware VST/AU ‘X-Orcism
It may be old news (2008) but the offer still stands !
From their website :
In response to ghost stories of economic doom and gloom we invite you to celebrate the festival of witches and ghouls with a bit of fun. SSL is proud to offer you ‘X-Orcism’, our free Halloween VST/AU format plug-in. Feed in your voice and you will be transformed into the voice of Halloween itself… be afraid, be very afraid.
Click here to download X-Orcism (Registration Required).