Originally Posted by
Woebegone
For achievements that involve catching other pets I suggest something that can heal itself without damaging the opponent or skipping turns. Celestial dragon is my favourite with the +10% healing weather effect and the powerful self-heal that also increases it's hitpoints. It can just sit there and take the abuse while I repeatedly fail my caging attempts and then move right on to next battle.
For pure fast damage I think you've already got it covered with spiders. Poison spit seems to penetrate all defenses, brittle webbing's damage reflection is insane against any attacks that hit you several times, the double heal from life leech against webbed opponents ensures you come out of even 1vs3 battles unharmed. The dot & reflection damage is just hopeless for catching anything - I barely ever succeed at caging the opponent before it dies.