With the Add-On Pack you get access to 28 cards: 24 additional creature cards (12 new creatures with duplicates) and 4 additional Mindbugs (required to play the 4-player mode).

List of creature cards:

• Bugserker (x2)
• Count Draculeech (x2)
• Creep from the deep (x2)
• Ferret Pacifier (x2)
• Froblin Instigator (x2)
• Goreagle Alpha (x2)
• Hamster Lion (x2)
• Hungry Hungry Hamster (x2)
• Hyenix (x2)
• Majestic Manticore (x2)
• The Lurker (x2)
• Turf the Surfer (x2)