The Earthlings in Toejam & Earl are no different.
When a Cupid fires an arrow at Toejam or Earl, they fall under a lovestruck stupor, and their D-pad directional controls are immediately jumbled (up becomes down, and down, up; or up is left and down is right - all manner of configurations are possible). Your controls remain in a state of disarray until the love spell wears off, so it's important to adjust quickly and get the hell out of there - each additional hit from Cupid's arrow not only refreshes the spell, but re-jumbles the controls as well. It's not until recently that I've realised this is a 'status effect' just like those found in RPGs (and of course, Roguelikes), albeit presented in a far more dynamic and tactile way.
Santa Claus is a similarly fictitious and random Earthling. You can never really tell when or where he'll make his next appearance. He seems to be attracted to levels with large expanses of water, but even that's not a hard and fast condition for a visit from this reluctant helper. I say 'reluctant' because he will only bequeath presents to those savvy enough to sneak up on him.
***As an aside, Toejam and Earl can sneak up on sleeping enemies (and Santa Claus) by holding down the action button. This is the default function of the action button, which I think is a great idea, and as a Sonic fan, I believe this should be implemented in most platformers. [One of the few frustrations I have with the Mario titles is having to hold down the 'run' button for the duration of entire games. It should be replaced with a 'walk' button, and Mario should run by default.] Back to sneaking: occasionally - perhaps once or twice during the course of an entire game - Toejam or Earl will let out an almighty sneeze, blowing their cover and waking up a sleeping Earthling (or alerting a rummaging Santa). If a second player is present, he will say "gesundheit", which is a nice touch to this well-loved cartoon trope. Similarly, Earl's pants fall down (much to his embarrassment) at random junctures, which never seems to get old. It's these spontaneous events that really contribute to this sense of a living, breathing world filled with living, breathing characters.
***When it comes to sneaking up on Santa, there is an added requirement for stealth success. The player has to sneak while he's rummaging in his sack, and stand dead still whenever he stops to look around. If the player manages to touch him when he's not looking, Santa drops an undetermined number of presents. If the player's spotted, Santa flies away in his jet pack to another random spot on the map. Both outcomes have an element of randomness.
There are Earthlings that likewise sneak up on Toejam and Earl, like Boogie Man for instance, but a far more compelling example of this can be found in the Mailbox Monster. Now, you'll likely encounter many a mailbox during the course of a game, but if you're anything like me, you'll damn near avoid the buggers every time. Walking past a mailbox is like waiting for the axe to fall, because the possibility of it being a Mailbox Monster is always looming. There's only two ways to find out if a mailbox is bonafide. Either you'll stand next to it, in which case it will offer a mail order (mailbox) or enter its frantic dance of death (Mailbox Monster). If you're lucky, you might catch an imposter shifting its eyes from side to side, and avoid such trial and error terror. The Mailbox Monster moves with existential panic, as if it's somehow shocked to be a monster, and that's what makes it dangerous.
There's only one 'Earthling' more erratic in its movements, and that's the Tornado. They can spring up from anywhere in the desert areas, but you can bet your bottom dollar - they're heading straight for you. It's nigh-on impossible to predict where a Tornado may take you once it's swept you off your feet, but its strong sense of sentient ill-will tells you it won't be anywhere good.
Which brings me to geography. The Earth, according to Toejam & Earl, is flat, perhaps as a comment on the backward savagery of its denizens. Each level of 'Earth' as it were, is a series of islands large and small suspended in space. This means there is an edge to every level, and Toejam and Earl can fall off, either through clumsiness (walking lovestruck in the wrong direction), item expiry (running out of Icarus Wings in flight), or enemy interference (the aforementioned Tornado drop). And when you do fall, you could land anywhere on the previous level. You could even land on a remote 1 x 1 square island, necessitating further falling until you can actually reach an elevator.
***Or you can do what my brother and I do, and that's fall right back down to Level 1 so that we can visit the secret Level 0. I won't spoil things by telling you how to get there, but I will tell you that once you fall off Level 0 you return to the furthest level you originally fell from to get there.
***However random it is, you do get a sense of the game's geography after multiple playthroughs. Quite often a secluded island can only join the mainland by revealing secret corridors, which are 'triggered' by surveying the coastline. In a puff of smoke, and the buzz of a sawmill, the corridor paves itself and winds its way across the void. Pursuing the new path often yields further revelations until it links with another body of land or intertwines with other corridors; other times it yields nothing and leads nowhere: random for the sake of random.
You can also reveal remote sections of the map at random by picking up a telephone, which - you guessed it - appear at random.
Speaking of telephones, or speaking of speaking, the conversation in Toejam & Earl also adds to its overall spontaneity. In a two-player game (yet another reason I espouse the superiority of the two-player TJ&E experience), the titular characters discuss all manner of things between levels, from the insanity of Earth's inhabitants to the awesomeness of their progress, to the origin of the smell in the elevator [hint: it was Earl]. While there are only so many conversations to be had between the two, you'll never hear the same conversation twice, nor will you hear them in the same order. There are other conversations to be had in-game, either in response to stimulus material ("aloha/hubba hubba" in the thrall of a Hula Girl, for instance), or to greet each other upon re-uniting.
And sure, sometimes it's hilarious, other times it's dated, but all of the time it contributes to the anything-can-happen-and-will thrill of this strange little game called Toejam & Earl.