1-whales accumulates the coin,that whale may have 10 btc to 50 btc,his name is usually captain, Yoda,owl,those wise name you would trust.
2-whale tell his friend to buy in the same coin.
3-all st, pump announce in the group.now you may think from the graph that you will at least get some gain, but the process is fast, i suspect their are using bots,the range is in Milli seconds.
4-you will see the coin mooning
5- you buy in.
6-if you panic sell fast at least you lost some but not all
7-Voila , now you are stuck in the bottom with a coin that does not matter wheter is good or bad, no body want tp invest in a dump coin.
So as tempting as it maybe be ,do not join a pump group.