I beg to differ sir
Not so easy Gatso, rarely if ever, will you see a yellow card for an indirect freekick offence. I believe it should be a yellow card and direct freekick, in this case it would be a penalty.
Player outside the field of play
If, after leaving the field of play to correct unauthorised equipment or
kit,
to be treated for an injury or bleeding, because he has blood on
his kit or for any other reason with the referee’s permission,
a player
re-enters the fi eld of play without the referee’s permission,
the referee
shall:
• stop play (although not immediately if the player does not interfere
with play or if the advantage can be applied)
•
caution the player for entering the fi eld of play without permission• order the player to leave the fi eld of play if necessary (infringement
of Law 4)
If the referee stops play, it shall be restarted
•
with an indirect free kick for the opposing team from the position
of the ball when play was stopped If a dog had run onto the pitch and stopped the ball crossing the line it would have been an indirect freekick that would be awarded. However the player here has committed a bookable offence by re-entering the field of play without permission and therefore a direct free kick (penalty in this case) should be awarded.
not sure if this rule covers dogs or not

Outside Agents
Anyone not indicated on the team list as a player, substitute or team
offi cial is deemed to be an outside agent as is a player who has been
sent off.
If an outside agent enters the fi eld of play:
• the referee shall stop play (although not immediately if the outside
agent does not interfere with play)
• the referee shall have him removed from the fi eld of play and its
immediate surroundings
• if the referee stops the match, he shall restart play with a dropped
ball in the position where the ball was at the time when the match
was stopped.