Each species of slime mold has its own specific chemical messenger, collectively referred to as acrasins. These chemicals signal that lots of individual cells should move towards each other to form a single large cell or plasmodium. One of the earliest acrasins to be identified was cAMP, found in the species Dictyostelium discoideum which exhibits a complex swirling-pulsating spiral pattern when forming a pseudoplasmodium.
The term acrasin was descriptively named after Acrasia from Edmund Spenser's Faerie Queene, who seduced men against their will and then transformed them into beasts. Acrasia is itself a play on the Greek akrasia that describes loss of free will.