Screen Bugs 1.1.0 for 64-bit Windows 10 (1607) or later.
Download ScreenBugs-Setup-1.1.0.exe and run it. There is no .NET prerequisite — the runtime is bundled. The installer asks which bug you want, how many, whether to run at sign-in, and whether to add a desktop shortcut. Those choices apply the first time each user runs Screen Bugs; if you have used it before, your saved settings are kept.
The installer is not code-signed, so SmartScreen will warn on first download. Check ScreenBugs-Setup-1.1.0.exe.sha256 against the file if you want to verify what you got:
Get-FileHash ScreenBugs-Setup-1.1.0.exe -Algorithm SHA256Silent install
ScreenBugs-Setup-1.1.0.exe /S /CURRENTUSER /BUGTYPE=HouseSpider /BUGCOUNT=12 /STARTUP=1 /DESKTOP=0
/ALLUSERS or /CURRENTUSER chooses the scope. /BUGTYPE takes Random or a species name — HissingCockroach, BlackGardenAnt, RedFireAnt, PrayingMantis, SevenSpotLadybug, StagBeetle, HouseSpider, Centipede, StinkBug. /BUGCOUNT is 1–50. /D=<path> sets the install directory and must come last, unquoted.
Uninstall accepts /S, and /DELETEDATA=1 to remove your settings as well.