The Pointless Museum web site has wonderful gallery of horror themed Top Trump playing cards.
Top Trumps was a slightly more complicated version of war. Simplified, you and another player compared “traits” and the card with the biggest number won.
Though many of the cards feature recognizable horror icons, my favorites are those that either botch known properties – like the dandy fop Godzilla in a cape and a gambler's tie – or use a known figure to illustrate some weird, ill-fitting generic horror type – such as the use of the robot from The Phantom Creeps as "the cannibal."
Plus, even I, Lucas, enjoy the card of the Fish Man!