The Otton Frog has sticky-out bits!
Each front foot has an extra digit known as a pseudothumb, and within it is a sharp spike.
Females almost never use their spikes, but males use them to fight each other during the breeding season. These fights are quite brutal, leaving the belligerents bloodied and scarred.
Males also lovingly stab their mate in the sides to ensure he has a good grip during sexy times.
All’s fair during love and war. ALL.
…Image: N. Iwai