The stats for a Rat Swarm are AC12 and 1HP. Killing one earns a Hero 1 Experience Point.
A Rat Swarm's tactics are -
If the Rat Swarm is within 1 tile of a Hero, it moves to the closest Hero's tile and attacks each hero with a multitude of Bites.
Otherwise, the Rat Swarm moves 1 tile toward the closest Hero.
A Bites attack gives a +7 bonus to hit and causes 1 damage.
The stats for a Spider are AC15 and 1HP. Killing one earns a Hero 2 Experience Points.
If the Spider is adjacent to a Hero, it attacks that Hero with a venomous Bite.
If the Spider is within 1 tile of a Hero, it attacks the closest Hero with an acidic Web.
Otherwise, the Spider moves 2 tiles (they're fast!) toward the closest Hero.
A Bite attack gives a +6 bonus to hit and causes 2 damage if it hits or 1 damage if it misses.
A Web attack gives a whopping big +11 bonus to hit (the highest of any Monster or Villain in the game) and causes 1 damage plus Slowed (a Hero' Speed is reduced to 2). In addition, place the Spider adjacent to the Hero.
The Rat Swarms are great sculpts. They do look very flat, which is why I photographed them from above. They are more a nuisance than a serious threat in the game. The Spiders, however, are fearsome opponents, fast moving, hard to hit and they deal out some nasty damage.