I can see evolution provide 1, 2, 4, and 5. 2, 4, and 5 all occur in nature now. 1 could be explained by other means. We are going to have to stretch to get the laser working.
As a base creature, we could start with some sort of Amphibian. Most Frogs, newts, salamanders and such can produce mucus of varying properties. One of them, in the case of poison dart frogs, is a strong alkaloid toxin. That gives you a bio-hazard. A big frog could also give your slip and fall hazard by leaving the mucus all over and if it doesn't evaporate quickly, you could step on a patch and take a tumble. So getting 4 and 5 together is pretty plausible.
Your evolutionary justification for this is some sort of boundary between a swamp and desert. Most likely in a river delta. The massive mucus production helps keep the Amphibian moist when a dry spell or hot wind from the desert threatens to dry our little friend out. The Toxin, and probable colorful markings, would be a warning for any birds that may view him as a tasty snack. 'Eat me, and you won't live long enough to reproduce'
Moving on to number 2. The Voltage hazard. Electric eels hunt by giving a stunning shock to their prey. Lets start with that, and have our little buddy evolve from an electric eel, keeping that electrical charge as its prime hunting mechanism. Remember, cute frogs are actually predators. With a stout shock, a frog may be able to take prey nearly as large as itself a little easier. So keep that mechanism as an evolutionary holdover.
That's 3 down, 2 to go.
Number one on your list, Radioactivity. Higher than background. Here is how we get to that. A little farther up the river there is a mountain with large deposits of Uranium. Rain and erosion wash a lot of this naturally occurring stuff downstream, where it settles deep in the delta where our little lethalissimus lives. He's going to absorb a lot of it as a function of his environment. Granted, it will match the background radiation of the swamp itself, but out of the swamp, his personal radiation will be relatively much higher. However they could also have a form of body chemistry which bio accumulates some of the radioactive daughter products; say strontium-90 phosphorous based bones. Due to higher availability of strontium vs calcium in that environment.
Finally we get to the lasers. sigh. I can't think of any way to produce a natural laser. Fortunately, you left me an out for light emission. Bio-Luminescence. Fireflies do this to draw mates, angler fish do this to draw prey, and so on. So the electric eel that is the forebear of our friend shared some traits with an angler fish with a lure to draw prey into electric stun range at night.
So what we end up with is a large Frog-like creature. Brightly colored with an appendage on either side of its body with a bioluminescent sack to draw prey, like a small bird, into stun range. Bird goes for glowy thing and gets zapped. During the day, other birds get discouraged by the brightly colored pattern that says 'stay away unless you want a terminal tummy ache' due to the highly toxic function of the mucus. The Mucus is produced in large quantities to help keep him hydrated in hot weather. The slow evaporation means slick surfaces every where he goes. And he is Radioactive merely due to the runoff from Mount Plutonium, and bio-accumulation of radioactive elements.