Party Line is the eighth episode of the Super Mario World animated series.
While out for a walk, Mario, Luigi and Yoshi begin discussing how dangerous it can be to live in Dinosaur World. As Mario says this, a dinosaur leaps in the group's path and shoots a fireball at them. Dodging the fireball as the dinosaur leaps away, Mario goes on to say that the citizens of Dome City have been having a lot of accidents lately. As if on cue, Yoshi trips on a used-up ? Block and falls.
Princess Toadstool suddenly appears to bandage Yoshi's wound. After having several large band-aids put on Yoshi's tail, the group is attacked by a giant Tyrannosaurus Rex. Running from this T-Rex, Yoshi ends up running straight into a tree. It is when this happens that Mario begins to wish everyone could just have an emergency number to call on the telephone when they got in trouble. Asking what a phone is, Yoshi is subsequently bonked on the head by a falling coconut before Mario can finish explaining what it is.
It is then that Mario gets an idea; using the two halves of a coconut and a vine, Mario creates a piece of communication equipment, in other words, a crude phone. Testing his device out with Luigi, Mario is overjoyed when he realizes it works.
Much later, Mario and Luigi have put together an expansive phone system with Princess Toadstool as the operator. Unfortunately, the phone-business gets out-of-hand, the Cave People are talking non-stop on their phones, the vine telephone-wires are growing all over the place, and the Princess is being completely overworked. To make matters worse, the Cave People have begun to neglect their duties, such as watering their crops.
Before Mario and Luigi can discuss matters further, they are suddenly attacked by a swarm of Caterpillars. While Mario is being chased by caterpillars, Luigi tries to call for help, only to get a busy-signal. Panickingly, Mario and Luigi climb up a nearby tree, this proves futile though, as the caterpillars simply climb after them, eating vines all the way.
Mario, trying to find something to fight the caterpillars off with, sees several ? Blocks floating in the air. Unable to reach a block, Mario is bitten on the leg by a caterpillar. This bite sends Mario leaping through the air, hitting a block and subsequently crashing down onto the ground, where he is surrounded by caterpillars. Grabbing the Starman that fell from the block, Luigi becomes invincible and, grabbing all the caterpillars, throws them into the tree. Grabbing a vine hanging off the side of the tree, Luigi pulls it, bending the tree. Luigi suddenly lets go, literally flinging the caterpillars into space.
After defeating the caterpillars, Mario and Luigi are approached by Oogtar, who says his phone is out of order and demands the Mario Bros. fix it. Before Mario or Luigi can say anything, they receive a call for help from Princess Toadstool, who has become trapped in a mess of vines. After freeing her, Mario, Luigi, and the Princess see a horrific sight - the T-Rex from before is back and hungrier, and the Cave People, being too busy on their phones, are completely defenseless against him.
Telling Luigi and Princess Toadstool to warn the Cave People, Mario tries to distract the T-Rex. Lunging at Mario, the T-Rex falls when Mario simply jumps out of the way. Getting-up, the T-Rex sees Mario hitting several ? Blocks, looking for an item to help him in battle. Getting nothing but coins, Mario makes a feeble attempt at defending himself by throwing coins at the T-Rex. Eating the coins, the T-Rex simply spits them-out disgustedly and hurls one at Mario's head, disorienting him.
Bouncing-off Mario's head, the coin hits a nearby block, which releases a Cape Feather. Trying to grab the feather, Mario simply stumbles to the ground. Luckily, Mario manages to obtain a Starman from a group of stars spinning around his head as a result; with the power of the Starman on his side, Mario grabs the T-Rex by his snout and hurls him into space, where he crashes into the same swarm of caterpillars that Luigi launched up there earlier. Mario then states "Call me Mario da Vinci! I've just invented the dino-copter!".
Rushing into a nearby house, Luigi and Princess Toadstool find a sleeping Oogtar, with a phone still to his ear. Taking the phone, Luigi and the Princess proceed to do the same with all the Cave People. All that's left to do is take down all the vines in Dome City, which Yoshi enjoys very much, as he gets to eat them all.
 Animation and Continuity errors
 Names in Other Languages