Trapinch, the Ant Pit Pokemon, was a Ground type introduced in Generation 3. Its evolution, Vibrava, the Vibration Pokemon, as well as its evolution, Flygon, the Mystic Pokemon, became the first Dragon/Ground type Pokemon. However, the typing didn’t stay unique, as the Gible line was released in the next generation, and they are all Dragon/Ground type. Nonetheless, Dragon/Ground is a decent typing. Ground gives Flygon an Electric immunity, plus its Levitate ability also gives it immunity to Ground type moves. However, even if Flygon wasn’t Ground, Electric moves are not very effective against Dragons anyway, and Ground types were never a problem for Dragons anyway. Instead, it gives Flygon a 4x weakness to Ice. The good news is that Flygon, although it is not a pseudo legendary, is pretty fast, so it might be able to get at least one hit on an Ice type before fainting. Now the question is, should you get a Trapinch in Sun and Moon?
Well, here’s the thing: Dragon types aren’t that useful in this game. The good news is that Trapinch is a pure Ground type, which makes it arguably more useful than a Ground/Dragon type. It also has 3 abilities, whereas Vibrava and Flygon only have Levitate. Arena Trap and Hyper Cutter aren’t all that useful, but Sheer Force, its Hidden Ability, can be pretty useful. It can get access to moves like Crunch, Bulldoze, Earth Power, Mud Shot, Mud Slap, Signal Beam, and Struggle Bug, all of which will be powered up. However, since Trapinch has a lower base stat total than its evolutions (although its Attack is higher than both of them), it can be quite weak. Giving it an Eviolite would make it more bulky, while giving it a Life Orb could make it a sweeper.