Mama Mush is obtained randomly when You Reach the Cub in the polar fields without the cookie.
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Angry Angry Arnold
You find him by playing the fishing game and winning an item with the word worm in it. The game can be found here.</p>
<p>Lizard Minion
You get him as a challenger when a random lizard event happens. The event says something along the lines of "You see a rare item on the floor. As you bend down to get it a lizard minion races in and tries to steal it." It doesn&;t matter if the lizard takes the item or if you beat him to it. Either way you should have a new challenger after getting this event.</p>
<p>Nightshade
You get this challenger by playing Dark Matter Dice or just refreshing on the first page of the game. The game is found here.</p>
<p>Mama Mush
You find her by going through the Polar Ice Field. You need to get to the spot where her cub is without a cookie. If you are very lucky when you get to that point she will attack you to defend her cub and be your new challenger. Good luck getting her since she is notoriously hard to find. Look for her here.</p>
<p>Recycle Beast
You get him as a challenger by buying something from his recycle shop. The shop is found here.</p>
<p>Saggitarius
You get him randomly while completing his quests. You can find his quests here.</p>
<p>Gelatins
These include Mini Gelatin, Gelatin Glider, Gelatin Golem and Hydragellos. These are war challengers. A limited number of each challenger is released during a war. Gelly wars happen about once to twice a year and will be announced on the news page.</p>
<p>Morostide
These include Deathly Harbinger, Torchbearer, Carrion Lord and Nightlady. In celebration of Morostide these challengers attack Subeta. It works the same way as the Gelly war in that a limited number of each challenger is released and we all get to fight them till they are all gone. Once again their appearance will be posted on the news.