Which level 2 creature is the best?

Elementals are the strongest of all second-tier creatures. Compare their stats – they are the fastest, have the highest hit points, attack, and defense, deal high damage, and fight in melee without penalty.

There is a penalty for melee combat. But I agree, they are the best. Where have you seen damage of 2-8? (it was written as 2-7 in the code, just a typo :) These are the stats for level 4. You just need to use Blink and be careful of lightning.