I was thinking of a new idea for an Invasion Critter.
There has always been a problem that critters that invade usually are too strong, or ones in the invasion will eventually be too strong for characters in lower trains to take on.
I was thinking a critter that is stronger when higher lvl characters attack it, but more vulnerable the younger the character.
One example:
An angry porcupine.
When a character attacks the porcupine it will receive its lvl/2 damage rounded up in retribution.
So if a lvl 100 character attacks the porcupine it will receive 50 damage back. If a lvl 1 attacks it, it will receive 1 damage back.
This could be taken one step further in having its AS fluctuate in relation to the lvl of the character it attacks.
I think this would put a nice twist on an invasion, making older characters run for the help of youngins.