Ghostbusters: Sanctum of Slime
12 Achievements
4-6h
COLORBLIND
Kill a Slime Abomination with the wrong weapon.
2.9%
How to unlock the COLORBLIND achievement in Ghostbusters: Sanctum of Slime - Definitive Guide
You can also damage the thing with the Yellow beam until he's about one hit from death and then just switch to the Red or Blue beams, it just has to be a killing blow with the incorrect color.
One thing to note is that, while the Red beam can penetrate through the machine, it's a bit finicky as to where you have to position it to damage him.
EDIT: It seems that the Abomination changes every time you die, so just keep dying to it until you get the yellow one, at which point do the aforementioned method.
Basically what you can do is attack the mob with its repected color and then switch to and other to finish him
The Slime Abominations are the larger enemies which throw goo trails at you. In order to unlock this trophy, you must be using the wrong weapon i.e. kill a yellow enemy with the red weapon. It's also worth noting that you must be awarded the kill so this is easiest to attempt in co-op as the CPU will more than likely use the correct weapons.
If they do use the correct weapons, wait until the enemies health is almost depleted and then switch to the wrong weapon and fire away.
Slime Abomination is these big ghost that rushes you and vomits at you and leaves a big trail of slime behind them. You'll first encounter one on the 3rd level. Be careful when facing them, because they only need one hit to down you. Too get this you need to kill a Slime Abomination with the wrong weapon, for example if the Slime Abomination is yellow you have to kill it with the Blue or Red laser. You can attack it with the right weapon at first, as they do more damage to him, and then finish him of with the wrong weapon when he is low on health.