Frog

The Frog is an enemy that appears in Crash Bandicoot 3: Warped.

Crash Bandicoot 3: Warped
They are primarily seen in the Medieval levels in Warped. The frogs hop around the path that Crash travels, and attack him by hopping towards his direction. Crash can usually avoid the frogs by simply dodging them while encountering them. He can also easily defeat the frogs by either jumping on them, or by spinning them away. If a frog attacks Crash and kills him, it will grant him a kiss, and afterwards turn into a Lab Assistant that resembles a prince.

Crash: Mind Over Mutant
The frog makes a cameo in Crash: Mind Over Mutant, where it is seen hopping around in the area with Crash and Coco's house and the Doominator ruins, where it hops along the lake, and can't be interacted with in any way.

Crash Landed
A frog would have appeared in Crash Landed, acting as part of the Frogzooka.

Crash Bandicoot: The Huge Adventure
This enemy also appears in Crash Bandicoot: The Huge Adventure. If a frog touches Crash, he turns green and falls to the ground.

Crash Bandicoot Purple: Ripto's Rampage
In Crash Bandicoot Purple: Ripto's Rampage, a frog is featured on a trading card.

Trivia

 * The frog kissing Crash and turning into a prince mirrors the Princess and Frog fairy tale, where a princess kisses a frog, who turns out to be a handsome prince after she kisses him.
 * In the second Medieval level, Gee Wiz, there is a frog who will bounce around in a puddle next to a Nitro crate. If Crash watches him hop around, he will eventually blow himself up by hopping right into the Nitro crate.