This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Woody Woodpecker
Woody's first appearance in "Knock Knock" is Deranged Animation. It does not help that when he first speaks, it is in a very normal tone compared to the later wacky tone he is known for.
The ending of "Pantry Panic": after Woody and the cat spent a good part of the short fighting over who would be dined by who, a moose happens upon Woody's door. They both rejoice at the sight ("Meat!" "Meat!") and the moose, terrified, runs away. Next shot is the moose's bones all piled up, with Woody and the cat next to them, having just finished to eat it... and the moose's dead head can be seen behind them.
Cat: "This was delicious, but you know... I'm still hungry."
Woody: (In an uncharacteristically even tone)"Yeah? So am I!"
[They draw their knives and get back to trying to kill each other.]
Barber of Seville, which is one of the 50 Greatest Cartoons, features Woody Woodpecker as a barber. The idea of this crazed nut with a razor is scary enough, but when he s l o w l y extends the razor as he glares into the eye of his current customer? Bring My Brown Pants.
The title card of the 1947 cartoon "The Coo Coo Bird" - the headshot of Woody from the side looks creepy.
In the cartoon "Alley to Bali" a Balinese woman tries to seduce Buzz Buzzard and Woody so she can sacrifice them to a cannibalistic evil spirit and almost gets eaten. The whole cartoon itself had a creepy and sinister vibe to it.
The evil demon statue is pretty nightmare fuel. ◊
The surprisingly creepy beginning of the official trailer for The Movie. For some reason, Woody's iconic laugh is slightly remixed to sound creepy, followed by an awkward close-up of Woody's uber-realistic face with jarring green eyes, while he says "remember me?"... over an unrelated shot poorly lip synced.
The live-action film has a number of moments where Woody is genuinely menacing, including a Shout-Out to The Shining.