You don't want a caster, and you don't want a low blue. You want as high a level as you can manage(you will gain skill faster) and something with a lot of hitpoints that will flee when it gets low enough. You beat it up while ensnared with the lowest damage/fastest two hand you can find.
A mob like:
https://wiki.project1999.com/Allizewsaur
And a weapon like:
https://wiki.project1999.com/Shovel
When it gets low on life and about to die, just camp out and right back in and he will have regened a decent bit of health but you should be able to quickly get him back to flee hit point levels with minimal mana expenditure and start all over again.