The issue is this line in your lists editor:

s = [mob.selectOne]

This means that every time you use s it’ll select a new random item from mob. The reason for that is because you’ve made s equal to [mob.selectOne] instead of mob.selectOne. The square brackets around it effectively make it “dynamically fetched” each time you access s.

You need to add [s = mob.selectOne, ""] in a place where it’ll get “executed” with every “generate” button click, so a new s is generated with each click, but it stays the same when executing all of the other square blocks that come after it.

So you could add this line before [output] in your HTML editor:

[s = mob.selectOne, ""]

Each time your “Generate” button is clicked, the update() function is called, and that causes all the square blocks in the HTML code to be executed from top to bottom. So it ensures that we’ve randomly selected a mob item and put it in the s variable before the output list is executed (which uses the s variable).

Here’s a fixed example: https://perchance.org/ylx7fmwpql#edit

(This issue has unfortunately been the source of a lot of problems for newbies learning Perchance, so you’re not alone in being confused by this!)

You can use the shorthand exp ? if_true : if_false notation chained together instead of the if ... else notations. It’s specially used for conditional inline value returns.

[s == "Wolf" ? wolf_gene : s == "Cat" ? cat_gene : s == "Fox" ? fox_gene : ""]

You can also do like this as well:

[({"Wolf": wolf_gene, "Cat": cat_gene, "Fox": fox_gene})[s]]