"I shall mount your head in my lair Ape!"
"Terra shall become my personal hunting grounds monkey!"
"When we are done your worlds will be nothing but burnt out cinders!"
"Bugs Bunny will pay for your incompetence with his life!"
"I take great pleasure in toying with you feeble Ape!"
Those are some of the ones that just popped into my head.
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"Your death is for the glory of Sivar!"
"I shall feast on your flesh Terran!"
"For the glory of Kilrah!"
"Your weapons are no match for my own!"