In Pokemon Magikarp Jump you will sometimes get Random Encounters that will benefit you in some way. These events are random but their effects are not. Check out this Pokemon Magikarp Jump Random Encounter Event List to learn what you have to look forward to.
Magikarp Jump Event List
After doing four of these, I jumped with a new Magikarp and it was snagged up by Pidgey. I assume it was eaten because I lost that Magikarp and had to get a new one. If you have a strong Magikarp it may be best to not do this.
The second time it was some Diamonds. If you choose to eat it you either get diamonds or lose your training bonus by eating glass. If you ignore it you get a small boost to jump.
The first time I had mine search and it made it back to me for a bonus to Jump.
When I waited the mayor found my Magikarp and brought it home and I got a minor jump bonus.
The first time I opened it, I got 12 coins. The second time I opened it, it turned into a Voltorb and it retired my Gold Magikarp. The third time I got 82 coins so the coins seem to be random or based on Generation because this was two generations ahead.
The first time I scolded him he ran off and I lost some Jump. Each time after he got mad and lost jump, not scolding him seems to be the best method here.
When I left him alone, he just went home and got some rest which increased my Jump.
The drink can be very helpful but it can also lose you Jump. If you drink it and you are out of training points, it can restore ALL of them. If it doesn’t restore your points though you will lose some drink. This is one I’d risk if I needed more training points because the lost to jump isn’t massive.
If you run away you get a minor boost to jump for free.
First time I ate it, it was a fishing hook and I lost some jump. The second time I ate it and gained a decent chunk of jump.
The first time I said yes Magikarp could gain an extra level, instead of 55 it could become 56.