Um, no they weren't. I don't see any good reason why they would need to be possessed
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I have a question, can Abe control whether or not the creatures he posses can explode or not? For example, in the first two oddworld games, excluding wildlife which I'm guessing since they were sacred creatures, they had some sort of immunity. But glukkons still blew up!
Yet in MO when you possessed glukkons, they wouldn't blow up, they just faint.