You appear to have 33.0 (thirty-three.zero) likely 33.0.2 as it was released on Oct 28 and not any 32.0.x version. The current 33.0 release is 33.0.3 released on Nov 6.

You can change you Homepage to something else besides the default about:home or do below.

Posted by cor-el:

That logo is one of the snippets that are used on the about:home page.

If you prefer not to see the snippets on the about:home page or otherwise experience problems with a snippet then you can set the browser.aboutHomeSnippets.updateUrl pref to an empty string on the about:config page. Delete the storage\persistent\moz-safe-about+home folder in the Firefox profile folder with Firefox closed ("3-bar" Firefox menu button > Exit/Quit) to remove snippets stored in IndexedDB and make Firefox use a default snippet set. You can reset the browser.aboutHomeSnippets.updateUrl pref via the right-click context menu to the default value to re-enable the snippets and make Firefox recreate the moz-safe-about+home folder. You need to close and restart Firefox after changing the value of the browser.aboutHomeSnippets.updateUrl pref.

You can use this button to go to the currently used Firefox profile folder:

   Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder) 

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

   http://kb.mozillazine.org/about:config 

Thank you for your response & suggestions. The about:home option removes crazy-tail logo but doesn't allow the regular firefox logo. The second option to delete the snippet folder & reset....I got as far as viewing the idb folder but the process you explained (very clearly) to reset is unfortunately way out of my league. (Tech stuff definitely not my strong suit). On Mozilla website I found earlier versions like 31.0 & 32.0 and tried to install both, but Mozilla's install process demands you press "upgrade" to continue with the install, so it keeps re-installing 33.0.3 instead of the earlier version. I even tried to install 31.0 version from soft32 but that didn't work either. I'm getting another laptop (windows 8.1) so is there a way to install an earlier version of firefox the first time without having 33.0.3 installed at all? Is this rediculous logo temporary or permanent? Can any of the add-ons help in this case? Thanks very much.

Alternatively you can use these steps to disable the snippets on the about:home page:

• Set the browser.aboutHomeSnippets.updateUrl pref to an empty string on the about:config page
• Open the about:home page in a tab
• Open Web Console in this tab (Firefox menu button > Developer or Tools > Web Developer)
  https://developer.mozilla.org/Tools/Web_Console
• Run this command via the command prompt of the web console:
  gSnippetsMap.clear()
• Close the tab with the about:home page
• Close and restart Firefox

The change in the logo on the default homepage is temporary, for the various promotional campaigns that Mozilla has run. Unfortunately, it appears to be the "new normal" now. When it was first started last spring it was like once every couple of months for a week or so, but now it looks like a "week on" and then in another week or two another promo starts.

Follow cor-el's instructions to lock the "snippet" from being downloaded, and then clear the current "SnippetsMap" via the Web Console.

Or, just set your own choice for your homepage. See - How to set the home page

Thanks for letting me know this logo change was temporary. I waited it out & the old logo is back....sort of. When I open Firefox the old logo appears, then the tail goes crazy for a second (extending like some serpent grabbing its prey), then immediately reverts back to the old logo. This I can deal with. Despite automatic updates my logo remained constant prior to this, so I appreciate knowing this is Mozilla's m.o as now I won't get as freaked out & waste countless hours trying to modify. Thanks again to you all.