An ant would not eat a slug because it is too big for an ant to eat.
anteater
A spider could eat an ant
Horned Toad (which is a lizard) .
Well if your talking about animals that at ants than many things including ant eaters
woodpeckers eat insectsinsectivore
ANT
I Don't Know try finding a slug and an ant...see what happens
An Ant Eater
An owl would
How an ant convinces anteater not to eat her
i think a cricket can not eat a ant (LOL)