One of the few bosses you’ll meet when exploring The Sewers after beating Radical Rat is Flushmaster. This fight may seem simple at first, but it can get quite annoying after it uses the same move every round. We’ll help you get through this mini-boss so you can face Boris and leave The Sewers in Mewgenics.
Flushmaster Boss Guide in Mewgenics

At the end of every round, Flushmaster will use the Flush move to push everyone 10 tiles back. This not only gets your melee attackers far from Flushmaster, but it also can harm any cats who are pushed into harmful objects like the spiky rocks.
You can avoid getting seriously hurt by making sure your cats aren’t standing in the same row as those spiky rocks. You can also position your cats near pipes, so when pushed into them, the cats will hit the pipes instead of getting pushed to the outer edge of the map.

I was able to stop Flushmaster from using the Flush move nearly every round by having my Mage cat use a spell that turned them into an ice block. This disrupts Flushmaster’s entire turn, and they are unable to use Flush until their next turn.
Upon defeating Flushmaster, they will leave behind Dip, the poop that was sitting on their head. End the fight by simply attacking Dip once, as it only has one HP.
