https://www.deviantart.com/thywordistruth/art/Toxicott-New-Fakemon-779656962

It's been over a year since I made my last fakemon, so we're due for another. I don't have a name for this one yet, but it's basically a big, gray otter that can poison things (so it's a water/poison type). In this lying-down pose, it is four feet tall from ground to head, and about six feet on all four. The whiskers attached to its snout can secrete poison at will, which is useful in battles, or for immobilizing prey. The black spiky fur on its back and tail can also secrete poison. A human that touches this poison will get sick and bed-ridden for a solid day, but can kill smaller creatures in mere minutes. Its bright, yellow underside is useful for tricking fish beneath it to swim up to it in curiosity, and before the fish realizes what it is, the otter easily snatches it up. These fakemon also tend to have a round, stout appearance because it needs that blubber to keep its blood temperature at normal rates in cold water. Adults grow to about the size in this reference, and newly-born pups range from nine-twelve inches long. Its diet is the same as regular otters; they are carnivorous, and feed on things like fish, crabs, oysters, etc.

Colors don't have to be ultra-specific; varying hues of gray, black, and yellow can be used, but that stark contrast between its back and underside is always there.