Lil Guy

Named baby animals will never grow up! Similar to Golden Danelions, they will stay babies forever.
"Naming" a named entity with an Unnamed NameTag will Unname the entity; this can be used to allow a baby mob to grow (though, they're vulnerable to despawning).
This mod was inspired by Scotty!
A sever I played on had a feature for keeping animals as babies but it did not work.
Scotty is fine but I wanted a reliable way to have this functionality.

Textures in screenshots and video are from Bare Bones by RobotPants.
All Versions
+ Add Version+ now uses 26.1 age-mechanics, where applicable~~~~
- Also includes 1.21 and 1.21.1 in this version
- 1.21.7
- 1.21.6
- Singleplayer Support (1.18-1.18.2)
- Singleplayer Support (1.19-1.20.4)
- Singleplayer Support (1.20.5-1.21.5)
- Named mobs DO NOT age. There was a bug where this was happening!
- Client-Particle BugFix
- Unnamed NameTags can be used to Unname entities
- Method-usage correction for version expansion: 1.21.2+ to 1.20.5+
edit: contains a bug where babies still grow.
- Unnamed NameTags can be used to unname a mob.
- Initialization Mixin Fix
- 1.21.5
- Named Tadpoles also nolonger age!
- Tested, works for 1.18.x (Not for tadpoles in 1.19)
- Would crash servers in 1.17 and below