While it is a pre-existing song, the lyrics of "Tom Tom" summarize Omni-Man's character arc to a T, meaning it makes perfect sense to play while he cuts loose against the Flaxans and unveils his true nature.
"I defy all the crooked little smiles of them": Omni-Man despises living on the imperfect Earth compared to Viltrum, and defies their will, demolishing their defenses progressively to prepare them for conquest.
"I defy the beady little eyes of them": Omni-Man slaughters the Flaxans with ease, tearing them apart and destroying their world.
"M-I-S-S-I-N-G, on god": Omni-Man is first in a coma after his battle with the Guardians, then disappears to destroy the Flaxans, disappears to fight battles and deal with disasters— he has a tendency to go missing from his family.
"M-Y-S-T-E-R-Y, on god": Nobody in the show knows who killed the Guardians. Meanwhile, the audience knows it was Omni-Man, but doesn't know why, leaving it the Driving Question of the first season and making himself and his agenda enigmatic and tense to the audience.
"Execution of a useless plan": Nolan's entire plan is destroyed by his all-too-human heart, with every day he spent on Earth ultimately falling apart when he can't kill Mark, blowing his cover and making him useless for infiltration, and being unable to kill the one person who might be an obstacle— in other words, his masterstroke was nothing but the execution of a useless plan.
"Execution of a useless/worthless/unjust man": Initially, Nolan considers Mark useless due to his lack of powers. Then, after Mark defies him, he sees him as worthless, a waste of time and effort when he needs blind obedience. Finally, Nolan realizes he does love Mark, and that the "execution" has been of himself— he's been arguing with himself all along, not Mark, and his actions are completely unjust, leaving him to fly off into space.
This just looks like twisting lyrics through personal interpretation to sound more applicable to the plot rather than Fridge Brilliance.
Removed:
This just looks like twisting lyrics through personal interpretation to sound more applicable to the plot rather than Fridge Brilliance.