Even if the card isn't a Rat itself, if it makes Rat tokens it also goes in, like Piper of the Swarm, Ogre Slumlord, and Chittering Witch
Magic: The Gathering custom card maker templates Template choice is mostly about aesthetics, but aesthetics matter when youre trying to keep a deck cohesive
It can become a big threat if left alone for long enough because it grows by at least +1/+1 per turn
A graded 10 copy currently commands about $1,400
Because right now, theyre out of control
Specifically when a level normally gates a desirable activated ability such as Enclave Cryptologist Agatha's Soul Cauldron clearly states " all activated abilities ", so all creatures with a +1/+1 counter at least gain the " Level up " activated ability and become able to put level counters on themselves with it (potentially making some creatures "Level up" cheaper and always easier on the colors thanks to the Cauldron's first line)