This mutant is the result of goodness knows what. Although fruits can fuse with one another during growth, plant form can diverge from normal via many factors. Some apple varieties, for instance, are prone to fusing two or more separate fruits into a single bizarre mass. The tissues will graft together. Examples are mutation from solar radiation, insect attack, disease and so on. And yes, despite its gruesome physical appearance of this strawberry, we ate it.
mutant strawberry seemingly growing an appendage