What does a coin crash/dump look like ?

I'm fairly new to crypto and so far only dabbled in BTC and ETH. But naturally our eye is drawn to these alt coins with insane returns. I'm looking at these meme/alt coins such as PEPE, SHIBA, FLOKI, etc and with 300% returns over a week they're obviously a pump and dump. Only those with crystal balls know when the dump is coming though, but it got me wondering:

What does a dump look like? Does it start slowly going down over the course of days or weeks or does it crash to 0 in a matter of seconds or minutes ? And what could likely cause a dump? Bots, whales or a combination of multiple factors ?

Thanks in advance everyone!