This is Ben first Ultimate Alien he used when his Omnitrix was destroyed by activating self destruct mode when he gave it to Vilgax. so he gets Albedo's Ultimatrix for a replacement and transformed to Swampfire standard form to defeat Vilgax then go Ultimate form.

Skin made by: Saito Moreno
Texture resized: Player9646
Saito Moreno YT Channel: https://m.youtube.com/channel/UCZhMBZoQe9VWxDTh-qfXxMA/videos