이거나 먹어라 = 이것이나 먹어라 = eat this / take this. It is a curse phrase usually said with a vulgar gesture showing what they mean by 이거 (this). It might be used by unruly children and teenagers, or in cartoons featuring them. You can't say it in any normal settings, but if you use appropriate tone and make no gesture, it will just mean "Why don't you eat this.", similar to 이거 먹어. (나 adds emphasis to 이거, like "Just eat this instead of looking for something else.").

"Eat this ～

'Take this! ( Throw something for another people, more Imperative. )' 이거나 먹어라 is a kind word of translate 'Take this!' for korean, especially in a Game. you can found like that a Overwatch, or Valorant. but '이거나 먹어라' doesn't have a especially a accent, so can say any form.