Pinkie Pie dressing Spike up in baby attires.
 
“Pinkie! I’m not a baby!”  
“Yes you are Spike!”  
“Damn it Pinkie! I’m 14!”  
“But you are still a baby silly filly! According to the guide to dragons by Tianlong Goldenscales, Dragons without emotion-bound growth spurt are classified as a baby for the first 40 years of his life!”  
“But Pinkie! That’s for…”  
“Yep, Dragons enter adolescence at 230 - 350 years of age, fully mature at 400 years, and considered middle aged at 2000 years, they could live for tens of millenias…”  
“Hey! B… but…”  
“That’s why you’ll have no chance with Rarity except she turns into Alicorn…”  
“NOOOOOO!!!!”