My Crazy Obsession 10 p.m., TLC

TLC — which, if I’m not mistaken, stands for The Look-at-People-With-Mental-Illness Channel — is finally eschewing the niceties and just going all-in with the C-word. Earlier this month, “My Crazy Obsession” bestowed upon the Internet one Eric Ducharme, a man fixated on mermaids to the extent that he has his own wardrobe of technicolor tails he wears to go swimming. Tonight’s episode will try to top that with a look at two men with a concerning relish for mustard and ketchup.

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American Idol 8 p.m., Channel 25

Now on to your crazy obsession. Tonight, the final four — Candice Glover, Kree Harrison, Amber Holcomb, and Beverly’s own Angie Miller (pictured) — compete for season 12 dominance. Fun fact: This is the first time in the show’s history that the final four has been entirely female.

The Rachel Zoe Project 9 p.m., Bravo

We’re gonna have to break up this whole outfit.

Restaurant Stakeout 10 p.m., Food Network

There’s not enough A-1 in the world.

Hoarding: Buried Alive 9 p.m., TLC

Emmy winner for pizza box in a supporting role.

Michael Andor Brodeur is assistant arts editor at the Globe. He can be reached at mbrodeur@globe.com. Follow him on Twitter @MBrodeur.