Herbivores that roam forested regions. Something has altered their hormones to the extent that they now sweat a strange black liquid. They are extremely aggressive , mercilessly trampling anything that draws near.
Enemy Intel
Mastodon is an enemy in Final Fantasy VII Rebirth, encountered in the Gongaga Region as part of the odd job "Teach Me, Great Warrior". After going through all the training segments with Sotetsu and reaching the "secret gym", two Mastodons will attack the party; in order to get the best outcome for the odd job, Sotetsu must not fall during this fight.
Stats
Battle
Charge.
The Mastodon is an unique and more powerful variant of the Elphadunk. It's an aggressive beast that attacks with powerful physical attacks.
The creature has two main attacks: Charge, where it runs towards the player character while swinging its trunk violently; and Rage, where it attacks multiple times by ramming against the character. Both attacks are difficult to avoid, but can be blocked.
If the Mastodon takes high magic damage or its elemental weakness is exploited, it'll use Seeing Red, which empowers all its attacks and make it even more aggressive. The condition lasts for around 30 seconds; after it ends, the Mastodon enters its Exhaustion phase, where it temporarily halts all movement and attacks, becoming vulnerable to attacks and susceptible to being pressure. After a few moments it'll use Breather, regaining back its stamina.
The Mastodon is weak to 
Fire.
Strategy
The Mastodon is sturdy and difficult to pressure, only after it goes on a rampage. Although this seems counter-intuitive, exploiting its weakness is actually the best way to dispose of it, by bombarding it with damage to defeat it before its fury lead to casualties.
The creature has no status resistances aside from petrification, meaning its susceptible to ailments such as 
Sleep and 
Stop, which can halt its movement and allow proper retaliation.
On Hard Mode, the creature is even more aggressive and it can enter its enraged mode easier. It can be easily crippled through Rancid Breath, learned from the 
Enemy Skill Materia. Defeating the two Mastodons on Hard Mode for the first time during the odd job "Teach Me, Great Warrior" grants Yuffie's Secrets of the Ninja Vol. IX.