It's the same exact player - the difference is :
The fish decides to shove with TJ against your pair of kings after a flop of K82 and you take all his money vaulting you to the final table with the chip lead.
The donk played the exact same hand the exact same way with the exact same flop (K82), BUT turns a Q and rivers a 9 for the straight, which cripples you, forcing you to shove ATC on the next hand, sending you to the rail on the bubble.